Im on Goodreads as an author too (I have no friends so feel free to friend me!
), but I do not sell via it. Goodreads just links to my Amazon and Barns and Noble listings. I have not found the "forums" there all that great but not spent much time in there. I need to start putting books I read in there and rating them to see how that goes... but so far I just have my author account and books I have written.