Here's some more information on Bungie's participation in PowerPlay, straight from Matt Soell:
Turns out we have signed on to be a part of the PowerPlay initiative. All that really means is that we want to decrease latency for net games, and hooking up with a whole lot of people with that goal in common seems like a good idea. Contrary to what the press release implies, this does not necessarily mean the PowerPlay standard will show up in Oni or Halo, because it's still very new and we just signed on. But we are helping to shape the standard as it develops and it could certainly show up in Bungie games farther down the line if it turns out to be as good as we think it might.
PowerPlay is a very new thing and we'll have to wait and see what effect the initiative will have upon the average end-user. However, I think such a collaborative effort is definitely a few good steps in the right direction.