Here's an interesting graphic from Brandignity on the psychology of social networking.

Some highlights of the infographic:

• Nine out of ten US internet users are on a social network. 
• One out of five minutes spent online is on a social network and that number is only increasing with time. 
• Although 80% of social media posts are about the poster, 9 out of 10 people think we share too much. 
• Facebook allows you to pay for your status update to be highlighted.
• Talking about ourselves is associated with the same satisfaction we get from food, money or sex. 

It ends with a question to think about while you’re posting your new status update on Facebook: Are we obsessed with social media or are we obsessed with ourselves?