This is something you all know. What I see is that they are mostly neglected because of Web2.0 fuss. This assumption is based upon my experiences of course. While Web2.0 properties have brought nothing positive to my sites, these sites, they are extraordinary: - pinterest - scoop.it - instagram - twitter - facebook (maybe digg) It may be time consuming but try to create accounts on these sites for every website you own and fill them with your own content. You may see good results like I do. PS: Sites are ordered by their effectiveness.