The O'Reilly Network has posted an article on retaliatory things people are doing against spammers (or, more accurately, against the companies that hire spammers).
One is a screensaver that participates in reloading the images from spamvertized sites. While the program may or may not bring down the site, the intent is to drive their bandwidth costs skyward, and hence raise the cost for them to do such business.
The other is a technique to replace the spam links placed in blog comments or wikis with links to an information site, but to leave the keywords intact, meaning that the info site (in this case, www.chongqed.org) will beat the offending site in the Google page ranks, and hopefully inform people to avoid such services.
Either way, it's another escalation in the arms race.