Many e-mail users are faced with the fact that not only important letters from acquaintances, but also intrusive advertising offers - spam - get into their mailboxes. But in order to send an email, you must first know the address. Where do the authors of advertising letters find the addresses of their "victims"?
The address can be stolen or bought
E-mail is not only a convenient and fast way to exchange messages, but also a fairly effective means of authorization on the Internet. On almost all sites where registration is required, users have to provide their email address. These can be free classifieds sites, job openings, hobby forums or online games - an email address is required everywhere. Thus, the site owners have a database of unique addresses that can be hacked using the program or, if the site owner is unscrupulous, buy from him.
The owners of large mail servers are periodically accused of selling email databases, but no evidence of such transactions was found.
Buying a database of relevant email addresses is not the only way to find addressees for advertising. Some spammers use various generator programs. Of course, not all addresses obtained in this way will coincide with real ones, but the very first mass mailing will allow you to weed out non-existent e-mail boxes, which will make it possible to compile a database of valid addresses, which can also be sold. Sending to cell phones is done in a similar way.
The popularity of social networks has made life much easier for spammers, as many users publish their e-mail addresses on publicly accessible pages.
Web search
Finally, the third option, which is used by many compilers of databases for advertising mailings, is the use of search engines and algorithms. The fact is that all email addresses have something in common, namely the @ symbol, which is called a dog in Russia. And search engines are capable not only of a regular search by request, but also of an extended one, using a specific syntax. You can search only in page titles or, conversely, only in their main part, search by part of a word or by one character in general.
This is exactly what the algorithm is based on: in the search string, a request is made to find the @ symbol surrounded by any other symbols. After that, it remains only to determine the actual addresses on the found pages. Of course, this is not done manually, but using simple programs. To keep their email address from being discovered by search engines, many people deliberately replace the @ symbol with the word "dog" or its derivatives. Such a replacement will not hurt a living person, but the search robot will no longer include the e-mail address in the search result.
