Controlling spam in signatures and "homepage" profile field
 

We desperately need a way to control spam in users' signatures and the "homepage" profile field. I also use another profile field to allow users to link to their blog, which attracts spam. In my opinion, the best solution would be to have profile fields and signatures be usergroup-specific and then disable them for your "new users" usergroup.

Does anyone else have problems with URLs and spam in these two fields? How do you deal with it? What would a good solution be?