Online Communication:
Facebook: As of right now, facebook is on top of the social network world. It has lots of different features and games, is extremely popular, and is a very easy way to connect with others. It isn't going anywhere for now.

Twitter: Although not quite on the level of facebook, twitter is closing in fast. It's popularity is skyrocketing and it has only just been started recently. It is somewhat limited by lack of features, but it still is going to be a major part of online communication.

Google+: Though it is not as popular now, Google+ is the networking of the future. Because of its ties with Google, the features for it are nearly endless. As it becomes more popular, it should become the #1 way of social networking.

Pinterest: Pinterest has some good ideas, but it will never be on the same level as other big networking sites. It is more a shopping-like site rather than communication.

Myspace: Myspace had its time, and now it's over. It is a internet ghost town, and practically useless. I doubt it will ever be considered relevant again.