How does antispam work on Mail.UA

1. A bit about the project itself

Mail.UA - Ukrainian web-based email service. For a long time, the project was under development and beta testing, but since the summer of 2010 registration for the service is free and, unlike other similar services, it is very simple: you only need to fill in 3 fields.
It is clear that all the usual webmail functionality is available. Among the features of the service include:

• Fast desktop-like web interface. Of course, AJAX will not surprise anyone now, but in the case of Mail.UA, the interface still deserves special mention.
• The ability to create an unlimited number of additional (temporary) email addresses to your main mailbox (more on this below).
• Anti-spam system based on the principle of "white list".

This article, in fact, about the latter features, because it causes the greatest number of disputes and ambiguous assessments.

2. About spam filtering in general

Usually some kind of special program deals with spam filtering, which among the many incoming letters tries to identify spam messages, according to the content of the letter to a certain set of filters.
However, there are two major problems inherent in all spam filtering systems:

1. Users still receive spam in their mailboxes and this, in general, is not so bad - after all, you can’t think of a protection that works 100%. It is much more unpleasant when a “false positive” occurs, i.e. Normal email is detected by the system as spam.
2. Worst of all, the user does not know how this system works and, in most cases, can in no way affect its operation. More precisely, it can sometimes (the “Spam / Not spam” buttons in Gmail), but not essential.

The main problem, it seems to us, is in the obsolete principle on which the anti-spam systems work. After all, before (at the dawn of the development of the Internet), most of the letters were “normal” and a smaller part was spam. Now (actually, how long ago) the situation has changed to the opposite: most e-mail messages on the network are spam.
Therefore, filtering should now proceed according to a different principle: we consider any incoming letter as spam by default and try to find conditions according to which it can be considered “not spam”. Those. Spam filtering turns into “not spam” filtering.

3. Antispam Mail.UA

Actually by such a principle it was decided to build an antispam in Mail.UA.
The question is: under what conditions will we select the "normal" letters? Given the second problem, we decided to take the principle of the “white list” as the main condition, which is formulated very simply:
If the sender's address is “familiar” to you (read: “is in the address book”), then the letter is not spam.
This approach has one indisputable advantage: now the user knows exactly what he needs to do in order for the letter to fall into his mailbox. The drawbacks of such a system are many, but all of them are solved by introducing additional conditions and mechanisms that help “good” letters get through the antispam filter. At the same time, the main principle remains unchanged, i.e. this is kind of our constitution. All the rest are laws that cannot contradict it.
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So, besides the principle of the white list, Mail.UA contains the following mechanisms for combating spam, or rather, eliminating “non-spam”:

• For registration on various forums, sites, etc. It is proposed to use temporary addresses. If your primary address is username@mail.ua , then temporary addresses will look like something@username.mail.ua . They can be made as much as necessary. Emails coming to these addresses are not filtered. If necessary, any temporary address can be closed at the reception or removed.
  It is recommended to create a separate address for each new registration - this way you will know for sure who sold your data to spammers.
• All emails from "unknown" senders are in the Spam folder. However, an email is sent to the return address with a link (if the corresponding option is enabled in the settings). Clicking on the link and passing the test “for humanity” (CAPTCHA), the sender can “push” his copy from the Spam folder into the Inbox of the recipient.
• Each user of the service receives a special personal page (business card) with the address username.mail.ua . On this page, by default, there is a feedback form with which you can contact the owner of the page (again via CAPTCHA-check).

The proposed scheme of work can be somewhat complex, but practice shows that the effort spent on its development pays off handsomely: there is practically no spam (only those letters that someone “pushed” manually), and all messages from various services are carefully arranged Daddies and marked with the necessary tags.
And most importantly, what the user receives is full control over the work of anti-spam mechanisms. Now only you decide which letters you want to receive, and which - no.
What happens with a different approach (when you trust solutions to a certain program), we all know perfectly well from the Terminator or The Matrix films :-).
In general (a little PR in the end), come in , try it yourself. As I said above, registration on the service is very simple and absolutely free.