Just Say NO to MLMs.

There may be a few legitimate multilevel marketing companies out there, but there are many that are nothing but some of then are nothing but schemes. In my opinion these schemes are one of the biggest nuisances on the Net. If these people manage to get your email address and think that you may be enough of a sucker to fall for their big offers, you get unending junk email.

The best way to avoid these jokers is by learning to recognize them when their emails arrive. If you come to a web page that is one big sign in a large font that tells you about this great deal, avoid it and don’t click it at all. Unfortunately many of these appear on many different freebie websites. If it looks like and MLM, if smells like an MLM or if it tastes like an MLM, avoid it.

Become hard to find.

This is probably the single best and most effective method of warding off the spammers. If you don't give out your primary email address except to trusted friends etc. and organizations you can keep a nice clean mailbox.
The best way to do this is to sign for the free online mail service providers like hotmail and yahoo. You can even get disposable email addresses that disappear on their own. Use these addresses when you think you may be exposed to a junk emailer.

When you do start getting too much spam to any of the free accounts just cancel it and get another one. You should also use a disposable account if you post messages to the Internet forums just to be sure. Spammers often use software that combs newsgroups for email addresses.