I just ran into a problem that I new would come up sooner or later, with the more sophisticated spammers. Someone joined my site and posted a generic, meaningless post on my forum and made their signature a link to their business. It was obvious spam. Now, on most forums the administrator has control over the signatures of its users, so that offensive or otherwise problematic signatures can be removed. I think that it should be possible for site administrators to "disallow" a users signature to appear on THEIR site, without it necessarily affecting the rest of wikidot. The reason I am bringing this up is for the case of removing someone's signature and warning them, without having to ban them from the site, etc.
However, for this spamming problem, I can of course remove the post and ban the user. However, would it be possible to put the same limitations on having a url link as a signature as we have on posts. Tied to number of posts in some way, or karma?
By the way, sorry, I forgot to properly tag the page. Thanks, Rob, for tagging it.