Spam filters are software that is either installed as part of an email client or part of the online webmail service. These are complicated in the operation, their back end logic, and how they are able to take over the ability to judge, for the user, which mail is spam and which are legitimate mails. This process is not completely foolproof, though you wouldn't find any of the mail users complaining about it. This is because bulk email and spam are fundamentally different from the perspective of the sender and not the receiver.



Most marketing material that comes in to a mailbox is looked down upon by most users and this is because of the common ancestry between spammers and bulk email marketers. Spammers indiscriminately mail and mail without getting the permission of the recipients to send mails. Bulk email marketers will mail a specific target group of possible buyers and are supposed to get their database of users only with an opt-in. However, bulk email marketers and anybody who sends mails are subject to the scrutiny of filtering mechanisms and if you don't already exist in the user's mailbox or in the address book and if you don't string your content properly, you will end up going to the wrong folder.

It is therefore imperative to understand how these spam filters work. Spam filters use a variety and a combination of different logical mechanisms to prevent spam. Some of these include maintaining DNS blacklists, collaboration with other email users, using special software to check images for color hues that remember human skin to screen out pornographic material, and complex mathematics. The filters that use complex mathematics are the most noteworthy because they are used in most webmail and in the more common email clients. Some of these use a mathematical function called the Bayesian method. This method looks for patterns of keywords in mails that are marked by the mail user as spam; thereby, learning the user's preference for spam. The other method is called Markovian discrimination and uses entire phrases instead of just single words.

This means that if you use your product names or brand names often enough in the email, it will be marked as spam. If you use typical marketing spiel, the phrases used will also be picked up as spam. Therefore, the best way to survive being scanned by spam filters is to make your advertisement a news article instead. The way news articles are framed and written, there is very little repetition and the brevity will work in your favor. You must also source your email addresses from sensible sources and not buy CDs of mail addresses off the market. There is no way that a customer is going to entertain you if you mail him or her without prior permission. So, get an opt-in by tying up with internet entities that might have synergistic interests with you. Also, use as much multimedia in your mails as you can.