Too many social networks?

Well, I have to keep my Linkedin, Facebook, ResearchGate, Plaxo, etc, networks updated and fresh. It is not working. I am not taking good care of any of them. They deterioate over time and finally I leave them. The addition of new forms of social networks for general and specific purposes is still growing fast. Where should I put my time and for what? Or is it time to leave them all and just stay in touch with friends and colleagues via email?

Fora.tv

Today I stumbled upon Fora.tv. They claim to be the YouTube for the thinking mind. I found some really interesting presentations. What was difficult to find was some kind of vision statement or purpose declaration, who they are and how they pick their material. I also had some problems with the "search", I entered some names but could not understand why I got the links that Fora listed. Anyhow, an interesting place to find high quality talks by thinking people.