Everyone needs to check out Why Am I Getting All This Spam? Unsolicited Commercial E-mail Research Six Month Report and heed the advice for avoiding spam.
Since I have my own domain name, we make a practice out of creating email addresses on the fly when asked to give out our email address. For example, if I need to give an email address to ABC Store, I provide firstname.lastname@example.org. I still receive all of the email in my “catch-all” mail account. This way I know exactly where my email address is getting out.
On a related note, Dan Benjamin announced the availability of Enkoder Form v5.0.