Social Networking Sites

My impression of twitter, Myspace, Facebook and Instagram are all the same in a broader sense because they all are networking sites that deal with communication or community. But in a closer view they are all very different because they all serve a different type of communication. If you look at facebook its pretty much all the other three in one. Although facebook has a status tool, twitter is all about status and tweets. Same goes for instagram. Facebook has a tools where you can upload pictures but instagram is all about uploading pictures and commenting on those pictures. Facebook as well allows you to share music and videos and myspace focuses on just that. If facebook is the full package then why does everyone use these other networks? Well when something is more zoomed in, its simplified and easier to use as well as easier to get a certain point across in a certain type of manner, using one type of communication instead of dozens.