Apparently, email marketing works much same way as search engine marketing does: in long run, you are rewarded for building (and sending out) trick-free, useful, and informative content.

So how should you build your business? One quality blog post, article, or email at a time.

Bayesian filters are better than traditional content scoring filters in that they are trained by you to recognize your email.

A doctor, for example, might have many emails legitimately using word "Viagra". A traditional content scoring filter would probably shoot that email to SPAM folder, or delete it.

This would result in a high false-positive rate for doctor, even if you don't want Viagra emails. The filter will build a list based on doctors email use and corrections to incorrectly marked email.

The initial training period may be a little time consuming, but once complete offers a tailored solution to SPAM control for each user.

In addition to protecting good email, filter makes it difficult for Spammers to trick as every filter will have individual requirements.

That being said, Spammers do have a few weapons in their arsenal to attempt to circumvent Bayesian filters. The easiest would be to create SPAM that looks like an everyday letter.

This would remove their ability to use typical marketing techniques and so is not as likely with normal commercial email. For purveyors of fraud, however, this would be easier.

Spammers could also so weight a message with a common good word, or distort bad ones, that it becomes scored as neutral or lower and get through.

Once correctly marked as SPAM by you, though, filter will adjust and not be fooled again. This automation and ability of software to grow as you and SPAM change over time is key to significance of these types of filters.

Widespread use of good Bayesian filters will not only eliminate SPAM on your end, but would reduce practice of Spamming altogether. If they cannot get mail through, they are just wasting their time.