In order to cut down spambots, I am suggesting to make people post 5 messages to be able to change their homepage and information tab.
Neutral on this, it doesn't really matter if they get a sliver of SEO, if that, from their profile. Actually, I don't see a reason for limiting that because it is no different than me putting my website on my profile and abandoning the forums. That would be considered okay since I've been an "active member," but in reality its not very different from joining, setting the profile site, and leaving. The only disruption is bots making threads about their websites. But either way I don't care since it doesn't affect me, just thought I'd voice some opinion.
No Support. I think its a little bit too much really. Some of the things on someones profile, such as details, are filled in usually when signing up. Also its easier for us to spot spambots cause of their profile page xD