I am pretty sure this is the first time I found a Web site promoting a link exchange tool specifically for forum signatures. If you want an example of a signature in a forum, take a look at my profile at SEO Chat, pretty ugly, heh... But that signature file goes on many of my posts at SEO Chat, possibly greatly manipulating (used that word for the search engines reading this) the results to boost my pages up to the top of the search result pages (again, its highly debated as to the affects, if any, that forum signatures place on SERPs).
A thread at Search Engine Watch Forums, and I am sure at many other forums, built a tool named SigTraders which helps the buyers and sellers of forum signatures transact.
