You can express yourself, showing off your favorite song lyrics or posting pictures of your new outfit. It is a lot harder to feel embarrassment over the internet than in person, so people find it easier to vent their feelings on sites like Facebook.
You can share your feelings and your mental stresses - and it is a great way to entertain yourself after a busy daily routine. Relax for users who want to find friends fun. And establish good relationship from friend to friend.
Social Network is a small corpus of knowledge because we can propose and comment, exchange of knowledge or questions on various matters for other persons interested or have the answer to help answer. And it can saves the cost of communicating with others. Also fast and convenient.