I was having a private discussion with Rojisan in #joiito who suggested to extend the mt-bayesian plugin to become an immunity system for the blogsphere when we got sidetracked.
One of the reasons we have blog spammers is because they want to get more links to their site and therefore higher Googlerank for their site. Therefore, if we remove this “feature” for them gain google rank, we would also remove the incentive for them to blogspam. Rojisan then gave me to challenge to the plugin in 30 mins so I did.
Download it here: mt-redirect-1.0.tar.gz (Documentation on Wiki)
Update 16/01: MT 2.661 already implemented this feature (and done it better) so go get it!