MovableType release the nofollow-plugin yesterday. The big search engines (Google, Yahoo!, MSN) and blogsoftware companies (LJ, 6A, Blogger) have defined a new standard to fight comment spam. All links added via comments are now extended with a
I am not yet 100% sure if this will solve the problem.
The plugin should work with the 2.661 version of MT, so I have installed the plugin, and if it works i will add the plugin to the FreeBSD port.