Google's got pretty good at working out which links are actually part of content, and which are just "decoration" in profiles, signatures and blog comments. They might make a difference still - but a minor one.
I think they're pretty much a waste of time as an seo tool, especially if they're put there by those dullards who join huindreds of forums just for the profile link, thinking Google won't notice how stupid they are. On the other hand if if spent years contributing to a niche forum there's no harm in having your profile show a link to a similar niche site.
I agree with Astroman. It definitely does not hurt, but don't expect much of anything to come about in terms of SEO.
A counterproductive link building strategy, though it gives you a very small link juice, considering the time it's taken its useless. There are much better free link building methods you can try out.
Quantum Leap was an awesome show, but that's a counter productive reply if you don't mention the other methods
Forum profiles will improve your position from no.1000 to no.960. on google, so if you are considering to pay for that service, better not
Yeah, don't treat it as something you should be spending all your time on for SEO. However, treat it as a way to open up networking opportunities with others
I use forum profiles for IP diversity mainly. Also for less competitive kws i can achieve top with just forum profiles,on page optimization and bookmarks from my experience.
In addition to if it is a do follow or not, the page rank plays a factor. There are so many other better things you can do instead of just relying on forum profiles... focus your time on better link juice than just profiles