Random Thought: Continuations to Fight Comment Spam
Not really, but the ugly continuation style URL's generated by FlowScript continuation ids in Cocoon can be used to fight them. Spam bots, I am pretty sure, presently rely on predictable url's for form posting. Via the common blog apps this is pretty easy to do. By using a timed unique link for comment posting you force them to at least interrogate the site and look for the posting URL -- but if all the URL's look like continuation ids they are doomed-ish =)
Aside from that Sam Ruby (visit his home page Google, type his name in, and hit I'm feeling lucky (thanks Erik!)) has posted a bunch of good ways to block this. Take back control of your server!