I was struck by this article from Jeff Jarvis:

Anyone who's used Twitter much will have noticed the frequent service outages - aka Whale Fail - after the image us users see then this happens. Given Twitter's enormous growth of the past few years (sometimes exceeding 1000%!) then the demands on it's central servers must be huge. Which is where p2p technology could help - as it scales with demand because as more people join they also bring their capacity too;