I know of one mountainbike forum which from time to time put interviews with famous users (for example because of very good riding video, etc) on the main page. I think this is a good opportunity for good riders to find sponsors and so on.

Translated to something like stack overflow this would be a good way for top contributors to get new clients/project/whatever and do some general advertisement for their own company.

edit: Examples in German:

http://www.mtb-news.de/forum/showthread.php?t=499722

http://www.mtb-news.de/forum/showthread.php?t=498160