In case you missed the announcement, Dave who developed Spam Karma is no longer going to make changes or update the code. Instead he has released it as GPL v.2 and created a Google Code repository in hopes that some talented people will pickup where we he leaving off. I wonder if we Spam Karma users had actually donated money toward his efforts if he would have continued.
Spam Karma puts Akismet and other spam fighting tools to shame. I think in all the time I have been using Spam Karma, I have had only one false positive. I get false negatives on trackbacks but that is because it was only recently that I realized I could change the settings for how Spam Karma handles trackbacks so I’m still making adjustments.
I also found Dave’s comments on a WordPress replacement very interesting. Specifically he notes, "If you look at it, blog systems are over 10 year old now. Their UI have barely evolved since the first versions. … There is a bad need for a groundbreaking platform that would get rid of ten years of accumulated UI habits."