On the audio side, there is a huge legacy interconnect system (POTS, or what have you). But on the video side it seems that you must have the same proprietary software on both ends. If you want to do Skype video, Skype must be on both ends. If you want to use Facetime, the guy at the other end must have Facetime, also. Same for the enterprise in-house network.
Anyone have any idea how this will play out so that you don't have to have five different softwares to make video calls with five different people?