Let's look at Web 2.0 from my perspective, traffic to my blog from Web 2.0 properties. By this I mean Digg, StumbleUpon, Delicious and our friend, Searchles. #1 The traffic does not convert well. But then again neither does most search engine traffic. #2 Social bookmarking traffic does not produce newsletter signups or blog comments. True, it does not from straight traffic, but if does from your friends list once you have set yourself up as an authority on your subject. I have gained many loyal and highly informed readers and bloggers who buy my products, hire me as a consultant, link to my articles and generate traffic for me. I know that this article is about revenue generated at Social Networking sites themselves, but aren't we using them for our own good to begin with? If we cannot generate our own revenue by using Facebook, then how will Facebook generate revenue by our use of it? Kimberly, you being in marketing, maybe you could provide a more elaborate view of this?