Social Networks, email, IM, voice, unified communications, SMS, VOIP and more.
Each one is made up of two many systems that are doing the same thing – each trying to dominate the market. There has to be something that would connect all of them together and will create the standard. Once they can all talk to each other then market domination will no longer be important. There are quite a few start-ups that aim to do that today – xobni, orgoo and more. Is any one of them doing a good enough job to unify everything? I don’t think so. There is a great potential to democratize the web on this