When I get spam I usually don't delete it (yet, at least). Instead, I throw it into a dedicated folder for storage. I guess one day if I ever need evidence, I'll have it right there.
I'm lucky enough that in the last couple of years, this folder still only has twenty emails in it. I'm also a bit irritated though that it's gone up from about 5 spam emails in the last couple of months.
The good news is that I know roughly where it came from. Virtually all the recent ones have been directed at a unique address that I only ever gave to realaudio.com.
There's a chance that it was picked up in transit somewhere, but considering that I only transmitted it once directly to their website (realplayer's never known it) about a year ago, I think it's more likely that they just leaked their database.
For the record with tricks to "discourage" people from signing off the list (which I wouldn't personally do anyway because it just confirms that the address exists), many of the recent ones I've received have had this on them (cut n' pasted):
Under Bill S1618 Title III passed by the 105th US Congress this letter cannot be considered spam as long as the sender includes contact information and a method of removal. This is a one time e-mail transmission. No request for removal is necessary.
At the moment, my strategy has been to forward everything I get for that address back to every realaudio administrational address that I can find (eg. root, abuse, postmaster, webmaster, etc). I point out that they might have a database leak and ask them to deal with it, let me know what happened, or at least apologise. (Ideally all three.)
So far I haven't heard anything, which doesn't inspire me with confidence. They haven't asked me to stop forwarding it to them, though.
The other thing is to make sure that friends and family know not to give it away. Every so often I have the problem where someone gives my address to a website so I'll get an electronic greeting or something. Whenever this happens I might thank them and be polite, but immediately ask them not to do it again and tell them why. As long as I'm polite it usually works. These days I also have an email sig asking people not to give my address to commercial entities without my permission. If anyone asks why, I tell them.
jesterzog Fight the light