Facebook isn't a Social Network,it's a Social Utility. But MySpace and Orkut are a typical Social Network. Further details are given below. Recently,Facebook came into limelight for disabling few user accounts just because those users were majorly spending their time on Facebook playing a game called PackRat.Facebook justified it saying that the game is so addictive that many guys create new Facebook accounts just for the sake of playing PackRat and not for the actual purpose of this 'Social Utility'.

Such accounts,which rather ill-utilize the 'social utility' are a burden to the website and hence may be banned.

The mail which was sent to the user who got banned also stated that

Facebook isn’t a social network (it’s a “social utility”) and isn’t meant to build large groups of new friends. Instead, Facebook is meant to reinforce “pre-existing” social connections"

After a lot of user outburst and a cluster of clarifications from FB guys,it seems that Facebook is firm on its definition of being a "social utility" and not a "social network" This is how Facebook defines itself(officially)

Facebook is a social utility that connects people with friends and others who work, study and live around them. People use Facebook to keep up with friends, upload an unlimited number of photos, share links and videos, and learn more about the people they meet

So what about MySpace and Orkut ? Are they Social networks or not ?