I am not sure about it that's why i am asking whether there is any benefit of your website in signature or not. If it play helpful role towards SEO then including website in profile is equally good or just link included in signature plays role.
SEO will depend on the site and how their URLs are design, both links and forum urls. As for working I can tell you right now over 40 people have signed up for my notification list in my sig from THIS forum in the past 3 days.
I think there is a benefit of your Web site in your signature. I can't say I get a whole lot of registrations through it but some are better than none. My sig isn't there for SEO.
The benifit of having a link in your signature is it will help get the site crawled. Other smaller benifits are that you can get some extra visitors to your site through the signature link and MSN, maybe Yahoo seem to count them for inbound links.