also, I was reading a very cool article in the December 2006 issue of Maximum PC, talking about different Gmail functions that I didn't know existed. A lot of the ideas where logical progressions if one just thinks about Gmail's power. I found the tip on a different site, but this one might help you guys with spam issues:
When asked for an email address, use something like "john.doe+amazon@gmail.com". That way, whenever you get future emails addressed to that address, you'll know that it's either from Amazon directly or from someone to whom they sold your email address. This can be a somewhat effctive way to track spam. Just be aware that not all email systems recognize or accept "plus" addresses. In fact, some spammers even strip it out completely, but it's a cool tool, none the less. THe best way is to just try it and see if it works for your application!
--I got that from this site:
http://g04.com/misc/GmailTipsComplete.html