Well basically someone has to be a 'host' or 'seed' or whatever you want to call it, the same way in P2P, but as someone is downloading/streaming off them... the next person can download/steam off either of these two, etc etc.
It's not bad, the only problem is if there's a big match on (I watch it for the soccer when it's not on my TV here) it becomes really slow and hard to find a feed (you actually have to HAVE one in the first place...)
But internet TV is certainly getting there.