Modwest Newsletter September 2006- SPAM is more than just a major food group.

Why am I getting spam? Canning Spam
Understanding and Putting a Lid on Junk Email

If you have posted on a newsgroup, bulletin board, or signed a web-based guestbook, spammers may have found your address that way. They also scour domain name registration (WHOIS) records, harvesting the email addresses of administrative, technical and billing contacts for domains; they often guess at possible addresses as well.

Full Newsletter: http://newsletter.modwest.com/2006sept/index.html