Yes, it will be quite interesting to see how well this works. My main concern is how quickly new spammers will be flagged as such. Right now, most spammers on my forum sign up overnight. Since I manually validate, by the time morning comes around, they may already appear in the Stopforumspam database or a Google search, giving me valuable information on whether or not to approve the accounts. With this automated system, I am concerned that if your system is hit earlier than most, the spammer will get through.
It would be nice if there were options to give higher scores (higher being more likely to be a spammer) to email addresses and IP addresses located within certain countries. On my forum, addresses/IPs from China, Vietnam, India, any countries in Africa, and Russia are 99.99% spam (I've only had a rare few valid Russian registrations). I know this would need to be on the client end, since there are obviously valid forums in at least some of these countries who would want people in their own country to register. :) But anytime I see an email address ending in ".in" or the IP location is "Nigeria", I don't even waste my time going further--I immediately nuke the account.
..Al