Inside Google, an article by Stephen Levy in Wired, looks at the software giant's plans to build a social networking service to trump Facebook's. Google+, the planned new service, is available by invitation only at this stage.

If you tweet and post, you might wonder how much influence you have. A new downloadable application, called Klout, aims to help you measure the impact you have in social networks. A Klout Score is based on 35 Facebook and Twitter variables and measures your true reach and score on each network.

The number of Americans using social networking sites has nearly doubled since 2008, and the user demographic is older - it's not just a young person's game any more.