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How postmasters of different mail services work

Today it is difficult to find an Internet project that would not communicate with its audience through Email. On the other hand, the monthly audience of Mail.Ru Mail is almost 23 million people. This means that among the recipients of your messages there will probably be many (even very many) addresses in the mail.ru, bk.ru, list.ru and inbox.ru domains. Let's face it, many popular projects have more than half of their users with addresses on mail.ru.

So what is Postmaster?

This tool is convenient, intuitive and simple as boots (at least it seems so to us). In order to start using it, you just need to add your domain to the project database and confirm the rights to it. This can be done in several traditional ways - by creating special file in the root of the web server, by adding a meta tag to the header of the main page, or using DNS check. Of course, you can add as many domains as you use in your project.

Immediately after confirming the rights to the domain, the following useful statistics become available to you:

  • Total number of emails sent
  • Number of complaints
  • Number of successfully delivered messages
  • Number of emails deleted as spam or marked as possible spam
  • Number of emails sent to non-existent addresses
You can observe all these numbers in dynamics over daily, weekly and monthly periods.

You probably know that SMTP protocol makes it easy to fake the sender's address. Therefore, to distinguish your mailings from spam ones, we use a DKIM signature. From here important note: For the statistics to work, your emails must be signed with DKIM. If your project doesn't already do this, set up your mail server now (it's easy; many modern MTAs support DKIM out of the box). By the way, this has a positive effect on deliverability not only for mail.ru, but for everyone postal systems and spam filters.

In addition, on postmaster we have collected more a large number of useful information for webmasters.

First, a set of rules that mailings must comply with so that they are most likely to successfully reach users' mailboxes. There is nothing unusual or taken out of the blue - all recommendations are based solely on common sense, based on RFC standards, the world's best practices in this area. As we pursue our goals, we must all remember that user comfort and convenience are ultimately what matters.

Secondly, we have published detailed transcripts of the most common errors mentioned in letters with “bangs”, which you can receive from our mail servers. And most importantly - brief and effective recommendations for their consideration.

Of course, postmaster.mail.ru does not cancel the address [email protected], to which we continue to accept all questions related to the delivery of letters to mailboxes in our domains, we carefully read and always answer. But we sincerely hope that the appearance of this tool will make your life much easier and your mailings more effective.

Of course, this is just the beginning. Our immediate plans include a breakdown of statistics by letter type (i.e. the ability to monitor individual mailings) and support for FBL technology. It will also be possible to get more detailed information about the effectiveness of mailings: the percentage of letters read, the percentage of deleted unread/read messages, the percentage of letters that ended up in the “spam” folder according to the user’s personal black list (personal antispam) and much more.

Our goal is to make postmaster.mail.ru as convenient as possible for you. Therefore, do not hesitate to leave your comments and suggestions in the comments. All of them will be read, analyzed and taken into account as much as possible.

Vasily Bespalov,
Head of Antispam [email protected]

The topic this topic is dedicated to is specific by definition – mailings. However, we are sure that some hackers sometimes use this type of communication. How to make it effective for you and painless for the recipients is written below.

Users often consider mailings that they personally subscribed to as spam, but formally this is not entirely true. But, of course, mailbox owners have no time for terminological subtleties - and, as a rule, they call any unwanted letters spam.

The purpose of the Postmaster.mail.ru service, which this article is devoted to, is to help web projects control the flow of electronic correspondence going to users’ mailboxes.

Since the publication of the new service for senders mass mailings, postmaster.mail.ru, we have received dozens of reviews and suggestions.

During this time, several thousand Internet projects joined the service (including very large ones - such as Groupon, for example). We take into account your wishes and will try to implement them all.

Over the past period, quite a lot of changes have occurred in the service:

  • The “Letters” section has appeared. In it you can see detailed statistics on different types letters.
  • In detailed statistics for a domain or for a specific letter, new counters have appeared (number open letters, the number of deleted open emails and the number of emails that were deleted unopened).
  • The interface has been partially redesigned.
  • The accuracy of statistics collection has increased.

Separate statistics by email type

In the new “Letters” section you can view detailed statistics for each type of letter. For example, you can view both statistics on user registration letters and, independently of this, statistics on password recovery letters.

To start using this new opportunity, you need to add a special header to each letter: X-Mailru-Msgtype. The value can be used random dial English letters and numbers up to 32 characters long. The header value will be used to group messages of the same type.

New statistics

It is also now possible to view statistics on letters, open by users. This unique information, since it is impossible to find out these numbers in any other way (and, as far as we know, no mail in the world yet gives senders the opportunity to find out such numbers). On the “Details” page for the selected domain or email you can see:
  • Number of open emails for the selected period (per this moment this is a simple counter of non-unique discoveries, i.e. If a user opens the same email 10 times in a day, then 10 will be added to the counter).
  • Quantity deleted emails, which were not opened. By this indicator you can judge how interesting the letters are to the audience.
  • Number of emails that were deleted after opening.

I would like to draw your attention to the fact that this statistic collected for the current day, i.e. if you sent, for example, 100 letters yesterday, and not a single one today, then the statistics for today on openings and deletions will not be zero, because users do not read your letters instantly, but with some delay.

All this, we hope, will help mailing list senders analyze the flow of letters more carefully and adjust it accordingly. better side, focusing on user reaction.

The immediate plans include the implementation of FBL technology (although this does not directly apply to the postmaster service), as well as - special API to access postmaster data.

We will be happy to read your feedback about working with postmaster.mail.ru in the comments or in a letter to [email protected].

Vasily Bespalov,
Head of Antispam Mail.Ru Mail.

In 56% of cases, the letter does not end up in the coveted Inbox folder due to the low reputation of the sender. What to do? - Read the article and you will learn what affects the sender’s reputation and how to track it using the postmaster.

Sender reputation

Task postal services- deliver a message that is relevant to the recipient, and leave unwanted messages outside the inbox. To sort emails into folders or discourage suspicious mailings, email providers rely on the reputation or rating of the sender. This indicator is shaky, and positive or negative points are awarded from the first mailing of the sender.

Algorithms for calculating reputation levels differ for all email services. Individual formulas are not advertised and include dozens of indicators and values, each of which is assigned a certain weight.

What affects the sender's reputation?

Technical specifications

  • Reputation of the sending domain and IP address

The sending history is checked: how long and in what volumes letters are sent from specified domain and IP addresses.

  • Key and DMARC protocol

These sender authentication methods indicate that the mailing infrastructure has been configured. They provide information about whether the domain has previously been used to send spam.

Qualitative indicators

  • Spam complaints
  • Non-existent users

These are addresses that have been deleted by the mail service or are no longer used by their owners. When you send a letter to non-existent users, you will receive a response. If you receive such an error message, remove the address from your mailing list so as not to risk the sender's reputation.

  • Spam traps

Used by postal services or specialized services anti-spam tool to identify spammers and block sending domains and IP addresses. Such addresses are specially created and then scattered throughout the network, where they can be parsed.

  • Presence of IP address in blacklists

You can check the health of your domain on the MXToolBox platform. Tool functionality for email newsletters includes a comprehensive domain analysis, correct operation And correct settings SPF, DKIM and DMARC, presence of addresses in blacklists.

  • Number of opens and clicks

A high open and click rate is a sign that the content being sent is interesting to the recipient.

  • "This is not spam" tag

Such actions of the subscriber are perceived by the mail provider as a positive signal - they want to read the newsletter.

  • Emails marked as spam
  • Forwarded emails

The recipient appreciates the received content and is ready to share it - such interaction has a positive effect on the sender’s rating.

  • Answered letters

This indicator most noticeably affects reputation in a positive direction.

Based on these metrics, a score is derived. It is expressed as a value from 0 to 100 or as a category from neutral to bad. The higher the rating, the more loyal the spam filter scans incoming letter. If you are a sender with a trustworthy reputation, the spam filter will forgive you a few words written in capslock. But if your reputation is tarnished, even a mailing list compiled according to all the rules can be filtered into spam.

Where to check the sender rating

The rating has been determined, what next?

What is postmaster

This is a tool provided by email providers. Using Postmaster, you can check the deliverability of your mailing list, find out how recipients react to letters, get information about spam complaints, identify errors that have occurred, and track the reputation of the sending domain and IP address.

Postmasters of different mail services differ in their functionality. When choosing an email analyst, consider which service the majority of subscribers use, or use postmasters from different providers.

How to connect postmaster

Step 1. Register an account on the selected email service, otherwise you will not see the data.

Step 2. Specify the domain and confirm rights to it.

Step 3. Make sure that email authentication is configured correctly, because the postmaster takes information about the domain from SPF, DKIM and DMARC records.

Let's look at how postmasters, popular among the Russian segment of email users, work.

Postmaster Tools from Gmail

Analytics are displayed in the form of tables and graphs for a period of 7, 30, 60, 90 and 120 days. You choose the desired period of time, but until the system collects a sufficient amount of information about daily traffic, reports are not generated. Statistics are visible only to those who send more than 200 emails per day to Gmail mailboxes.

The following statistics are available in the service:

  • getting into spam, where the percentage of emails that users marked as spam is indicated. Only those messages that are signed with a DKIM key are taken into account;

  • IP address and domain reputation. These are two separate graphs. Reputation is calculated based on the sending history, the volume of emails sent and feedback from the recipient;

What is the reputation of an IP address:

Bad(red). A lot of spam is sent from the IP address.

Not very good(orange) . A significant amount of spam is sent from such an address.

Satisfactory(yellow). Emails from this IP address periodically ended up in spam.

  • feedback or Feedback Loop. First of all, set up the headers for FBL. You will see a graph with information on problematic identifiers;

  • authentication. The panel displays the percentage of emails from all outgoing traffic that passed SPF check, DKIM and DMARC;

  • encryption, where you can see what percentage of incoming and outgoing emails in relation to the total volume passed the TLS check;

  • delivery failures. Shows the percentage of rejected or undelivered messages;

Yandex Post Office

In Yandex Postmaster you can view statistics on separate domain, several domains or IP addresses and each letter. Analytical data on mailings is displayed if you send more than 100 letters to Yandex mailboxes.

The results of the mailings are presented in the form of a table, where you can see the number of letters sent, the percentage of read and unread letters, deleted messages and those that ended up in the Spam folder. The most effective mailings are highlighted green, and letters with a low score are shown in red.

Emails can be sorted by subject, sender, date, and mailing ID.

To call up detailed statistics on your newsletter, click on it and you will see a pie chart.

The outer ring of the circle shows the proportion of read and unread emails. In inner ring more detailed information is stored. Hover your cursor over the sector of the diagram you are interested in and you will see:

  • the number of read letters that remained in the inbox;
  • number of unread messages in the “Inbox” folder;
  • share of deleted emails;
  • percentage of emails that went to spam.

When you click on each sector of the chart, a separate graph will be displayed:

  • in the read emails sector you will see how many emails are in your inbox, deleted after reading and marked as spam after reading;
  • V unread messages there is data on what percentage of letters remain in the mailbox, are deleted before being read, and are marked as spam even before the letter is opened;
  • in the deleted messages sector you can see the number of deleted messages before reading and after viewing;
  • spam emails show the percentage of messages that Yandex spam defense did not miss, the number of emails that ended up outside the inbox due to personal filtering, and the portion of emails that went to spam before and after being read.

The Yandex Post Office gives users tips on how to improve mailing efficiency - you will find them on the detailed statistics page. Blocks with additional information are available in the same tab.

Click on the block you are interested in and get a graph:

  • average percentage viewing the letter;
  • average time spent reading a letter;
  • average time from receiving a letter to reading it;
  • at what time of day subscribers read emails most often;
  • demographic data - gender, age, income of the audience and the percentage of how much the recipient is interested in the subject of the newsletter.

Postmaster Mail.ru

In Mail.ru postmaster, analytical data on a domain can be viewed for a selected period - 1, 7 and 30 days. The information is divided into three tabs: statistics for certain period, graphs for one or more parameters and problems with letter delivery.

Statistics tab

  • Letters - the total number of letters sent to Mail.ru users.
  • Complaints - how many emails are marked as spam by recipients.
  • Reputation - the average percentage of spam complaints over the last 30 days.
  • Trend - change in the percentage of complaints over 7 days relative to this indicator over 30 days.
  • Read - the number of open messages.
  • Deleted reads - the number of messages that the recipient deleted after reading.
  • Deleted unread - the proportion of emails that went to the trash bin before they were opened.
  • Delivered - percentage between letters delivered to the “Inbox”, “Spam” folders and those that were not missed by Mail.ru servers.

Reputation - important indicator in this table. To prevent the domain from being blacklisted by the service, carefully monitor it. Depending on the number of emails sent, there is a peak complaint level that cannot be exceeded:

  • if you send less than 10,000 letters per month, the limit is 1.4%
  • less than 500,000 - 1.3%
  • less than 10,000,000 - 1.1%
  • less than 50,000,000 - 0.7%
  • more than 50,000,000 - 0.4%

Charts tab

It presents a chart with increasing and decreasing bars for the selected indicator.

Problems Tab

Technical problems with the domain are displayed, due to which statistics are not collected - lack of SPF, DKIM or DMARC, letters that were sent to non-existent addresses, and those that were marked “Spam” by users.

Section "Letters"

Here you can see general statistics for individual letters. Mailings of the same type are grouped and for each of them you can see the number of letters delivered to the inbox - green sector, ending up in spam - yellow sector and rejected by the server as spam - red sector.

Statistics are collected if the letter has a special header - X-Mailru-Msgtype. To group messages, enter a header value. Any combination is suitable Latin letters and numbers no longer than 32 characters.

Conclusion

  • carefully monitor the delivery of letters,
  • look at the interaction of subscribers with the newsletter and try to ensure that the level of complaints about spam does not exceed 0.2%,
  • track delivery errors,
  • Regularly clean your database of invalid addresses.

Hurry up, connect the postmaster and high ratings to you, sender! And to find out how to avoid getting into spam, watch this video and go to Youtube channel SendPulse, there is still a lot of useful stuff there.

You can make a useful newsletter with good text, beautiful design and high-quality layout, and then see that two and a half people read it (you are among them). And all because your letters ended up in spam and did not reach the final recipient. You must not only be able to make mailings, but also deliver them. This cannot be done effectively without high-quality analytics.

Postmasters is a tool for analytics of your mailing list, which is available in all the most popular email providers: gmail, mail.ru, yandex, hotmail, yahoo, aol. They help you find out your spam rating, IP and domain reputation, delivery errors, and improve your mailing deliverability based on these indicators. Whatever postmasters we are talking about, for them to work, DKIM (Domain keys identified mails) and SPF (Sender Policy Framework) must be configured - these settings are needed to identify and authenticate the sender. Without these settings, postmasters will work, but not completely; mainly, the FeedBack Loop function, with which you can find out how a subscriber interacts with the letter, will not be available.

Almost every major mail service has its own postmasters. Each has its own, that is, after setting up the postmaster on mail.ru, it will not work on Yandex or Google. There you will need to configure your postmasters. They all differ in interface and slightly in functionality. Set up postmasters for the services you send to. significant amount letters.


Feedback loop - a function thanks to which we will receive a report on who clicked the spam button, and thanks to this we will be able to guess why (for example, looking at the history of his interaction with the mailing list). And this information can already be used to adjust the mailing list and reduce getting into spam. By default the feedback loop is disabled, it needs to be configured.

Delivery Errors Dashboard feature displays delivery errors. There are many reasons for these errors: bad reputation IP or domain; attachments that gmail does not support; spam content; DMARK check failed. And this is not the whole list. In the report you can see detailed information on each error; just click on it. Encryption Dashboard shows the ratio of the total number of letters to letters with TLS (Transport Layer Security) code. Messages with this protocol are protected from unauthorized access.

There are companies where mailings are sent to a database foreign addresses. Your clients from New York have heard something about Yandex, but know nothing at all about mail.ru, but they themselves use mail from Yahoo. We will now consider this postmaster.

Yahoo

Go to Postmaster, click New Sender Application, fill out the form. We are now registered as a new sender. After that, click Feedback Loop Application and also fill out the form. This is how we apply to connect the Feedback Loop. After this we get Mailbox [email protected](on your domain), where reports on the work of the mailing list in yahoo mail will be sent. From them you will find out how many times your mailing was marked as spam. Separately worth noting feedback that this service provides. All communication takes place on English language, but users actually get questions answered. There is a forum where you can ask a question. The forum is live, it is quite possible to get an answer to your question.

AOL - American Online

AOL (American OnLine) has had its own since 2004 mail client. Today the company owns such brands as Moviefonet, Engadget, TechCrunch, MAKERS, and Stylelist. AOL has a postmaster, which we will look at. Here more features, and the menu is more friendly than in Yahoo.

The AOL postmaster has his own blog where he publishes last news and changes in the operation of the service.

We go to the postmaster, we see three menu items: popular links, tools and technical assistance, reference information.

In chapter popular Links Can:

  • view error codes;
  • add your IP list to White list(does not work if it is already blacklisted);
  • apply to connect FeedBack Loop;
  • create a bug report. There are several types of errors in the menu, which give a short description of them, and what needs to be done before writing about the problem. When you click the create button (error name) ticket, a convenient form opens for filling out information;
  • AOL mail servers. Changes to your mail servers are displayed here.

In chapter Tools & Technical help Can:

  • check IP reputation;
  • verify the IP connection. You should go through this verification if you are not sure whether your emails pass through firewalls and proxy servers or not.
  • Read the instructions for passing the Telnet test. It is needed to manually configure mailing list via Telnet.

AOL's Postmaster interface is much more user friendly than Yahoo's. The service has existed since 2004 and has been actively developing since then. In 2012 they updated the design and recently added integration with Outlook Express. If you work with mailing lists in the Western market, we recommend setting up a postmaster from AOL.

All of these postmasters are largely similar in function or settings requirements, but some stand out from their competitors.

When Google launched its postmaster a year ago, it did not have full functionality as it does now. Much was added that same fall. Now we see that the yahoo postmaster is a bare FeedBack Loop - almost no one does this anymore. It is logical to expect changes in the functionality of this postmaster. If they are significant, we will definitely report about it on our blog.

Set up your postmasters and welcome to your inbox!

And in this one, we’ll talk about such a tool as the postmaster.

Postmaster in in a general sense is a tool provided by an email provider to analyze the results of mass mailings.

This tool will help you find out the delivery rate of your mailings, the reaction of subscribers, as well as some problems that have arisen. This information will be useful when planning and optimizing your future email marketing strategy.

Let's consider the capabilities of postmasters of the most popular email platforms, namely:

  • Postmaster Mail.ru
  • Post Office Yandex
  • Gmail Postmaster
  • AOL Postmaster
  • Yahoo Postmaster
  • Postmaster Outlook.com

Postmaster Mail.ru

How to connect?

To connect to the Mail.ru postmaster, register your mail in Mail.ru and go to the postmaster page.

Mail.ru interface

To display statistics, you must confirm rights to the domain with any of three ways: HTML file, meta tag or DNS check. If rights check is successful, statistics on this domain will become available.


Confirmation of domain rights in Mail.ru

What can he do?

Postmaster Mail.ru provides access to mailing statistics, grouping it by day, week or month.


Mailing statistics in Mail.ru

Among the proposed parameters:

  • Letters - number of letters sent;
  • Complaints - the number of clicks on the “Spam” button;
  • Reputation, % - average percentage of complaints over 30 days. It is calculated as the ratio of the number of complaints over 30 days to the total number of submissions during this period of time and is expressed as a percentage;
  • Trend, % - change in the percentage of complaints for 7 days in relation to the percentage for 30 days;
  • Read - number of open letters;
  • Delete read - number of messages deleted after reading;
  • Delete unreadable - number of messages deleted before being read;
  • Delivered, % - percentage following types letters:
    • Delivered - the number of emails delivered to the Inbox;
    • Possibly spam - the number of emails delivered to the Spam folder;
    • Exactly spam - the number of letters that were not accepted by Mail.Ru servers. In response to such letters, you always receive a letter with the error 550 spam message discarded.

Most important characteristics here are the current reputation and the percentage of delivered letters. These criteria most clearly reflect the state of the mailing list and its dynamics,

The graphs on the adjacent tab clearly demonstrate the dynamics of a particular indicator:


In addition to grouping by day, it is possible to see general statistics By individual messages. You can do this on the “Letters” tab. This type of grouping is useful if several letters were sent on the same day and you need to see statistics on complaints and deliverability for each of these letters.

Mail.ru Postmaster supports FeedBack Loop technology. We've already told you about it. To connect to FBL, you must specify the email address to which reports will begin to be sent. This can be done on the settings page.

Unfortunately, the postmaster does not have open API. The absence of this feature will complicate the implementation of automatic uploading of reports. .

Post Office Yandex

This service is useful for email marketers, as it provides large volume data, thanks to which you can improve your mailings and make them more effective.

How to connect?

To connect the Yandex post office, register your email and go to the post office page.

Enter the domain in the field that appears and click on the “Add” button:


After which the service will provide setup instructions:


After confirming rights, the domain will appear in the “My Domains” list on home page service.

To set up FBL, you must request activation through the form via the link. At the same time, for Yandex it is impossible to configure FBL for a specific domain; you only need to specify the pool of IP addresses from which your messages are sent.

What can he do?

Yandex post office, just like Mail.ru, provides access to detailed mailing statistics.

On the domain statistics page, the grouping is by message subject, sorted in chronological order, in contrast to the “Subject” tab, where messages are sorted alphabetically.


Example of Yandex statistics

Clicking on the letter opens detailed statistics in graph form:


Need more?

Additionally, you can view more complete statistics:


Particularly interesting here is the statistics of subscriber activity over time and within the letter. From here you can find out how many people viewed the letter to the end, how much time subscribers spend reading the letter, what time of day they open it, and how much time passes from the moment they receive it to reading the letter. By analyzing this information, you can adjust the time of sending the letter, its length and the volume of texts inside, which will improve the effectiveness of mailings.

You can also download all statistics on the letter in the form of a pdf file from big amount various graphs.

When you first log in, you will be prompted to add a new domain:


You can also do this by clicking on the “Add” button on the main page of the postmaster.


In addition to confirmation via a TXT record, it is possible to use a CNAME record for authentication.

After confirming the domain, it will appear in the list of domains on the main page of the postmaster.

What can he do?

Gmail Postmaster allows you to get less detailed information about your mailings. Among those available:

  • proportion of hits to spam;
  • IP and domain reputation;
  • information about authentication (passing DKIM, SPF and DMARC checks);
  • information about traffic encryption (TLS share);
  • information about delivery failures.

FBL mechanism is also available.

All reports in Gmail Postmaster are generated in the form of graphs and tables with a selection of data for a period of 7 to 120 days.
Please note that information in the reports may be missing if there is a small number of sends to Gmail mailboxes. The data will begin to be displayed when there is a sufficient amount (hundreds of records) of daily traffic data.


Example of a report “Proportion of hits to spam”

Gmail Postmaster is not the best handy tool for analyzing mailings, but clearly shows the dynamics of domain and IP reputation and statistics on the passage of , and .

AOL Postmaster

Unlike the services above, AOL Postmaster has other functions, the main ones:

  • the ability to whitelist your IP;
  • IP reputation check;
  • IP verification (checking the use of firewalls and proxies);
  • database of returned error codes.

These functions are available without registration. To use them, you need to fill out and submit the appropriate form.

To set up FBL, submit a connection request by filling out this form.

After filling, click on the Next button.


AOL Postmaster Form Example

On next step select mailboxes for confirmation (3 options are offered: [email protected] , [email protected] or [email protected]) and domain IP addresses.

After filling out the form, an email with a link and confirmation code will be sent to the selected address.

After confirmation, FBL reports will begin to arrive at the email address specified in the first step.

Yahoo Postmaster

Yahoo Postmaster also does not provide mailing statistics; its only function is FeedBack Loop.

To connect, we need an account in the service. After registration, go to the postmaster page.


To set up FBL, follow the link and fill out the form.

After sending the form to your mailbox [email protected](don't forget to set up this mailbox on your domain) a confirmation code will be sent. This code must be entered to confirm rights to the domain.

As soon as the domain is confirmed, reports will begin to be sent to the mailbox specified in the form.

Postmaster Outlook.com

On the Junk Mail Reporting Program page, fill out and submit the form:

Here you must enter all the IP addresses from which newsletters are sent. When you enter your IP address, the service offers a choice of mailboxes, to which, after submitting the form, you will receive a letter with a confirmation link. You need to cross it.
Also, a contract will be sent to the contact box indicated above using the docusign.net service, which must be signed to complete the account setup.

After all requirements are met, notifications about complaints about mailings will begin to arrive at the specified mailbox.

Outlook.com Services

  • monitor the reputation of your IP addresses in the Microsoft ecosystem,
  • determine Accounts users or computers used to send spam email,
  • remove complaining subscribers from the database.

conclusions

By correctly using the tools described above, you can significantly improve your mailing performance and make your emails interesting and convenient for subscribers. By tracking your delivery rates you will always be in the know. current situation both from a technical and qualitative point of view. And the FBL mechanism will allow you to avoid sending letters to uninterested recipients.