One of the most interesting things to me about the Internet is the struggle between spammers and end-users who don't want to get spam. There is a lot of good spam filtering out there now, but in my opinion we will never significantly reduce the nuisance of spam until we come up with a new mail transfer protocol that can actually verify the sender somehow. I'm working on this along with I assume the rest of the population.
In the meantime, the back-and-forth is fun to watch. One new technique I'm noticing is that you'll get a spam email that is basically just text pulled from some news site, and the link to whatever site they are hawking is just there in the middle.
This is a neat innovation. Annoying, but neat.