You guys are doing a great job in keeping the board clear. Many congratulations for spending the time to do so.

Can I add a couple of points?
One small observation is that in most of the multiple posts I've seen and reported recently that some of the posters are simply copying Pratchett related text from other sources and adding the spam links to their signature line. Would a security question be as easily bypassed with a simple google search?

Most of those people fill in the minimum details - would it be possible to make a few extra deatails (eg. email, which can remain hidden) compulsory on the initial form? It might make the process a bit longer and discourage them.
Or simply have their membership held until approved by the Sweepers.

Does akismet read the signature as part of the post or would it ignore it?

I want to die peacefully in my sleep, just like grandpa. Not screaming and panicking like his passengers.
Don't drink and drive from The Lancre Tavern