I think the point is that just because there is an dominant player in an industry, doesn't mean they will remain dominant. How easy it is to disrupt a market v

I think the point is that just because there is an dominant player in an industry, doesn't mean they will remain dominant. How easy it is to disrupt a market varies, but they all will change over time. Facebook's open graph actually makes it much more likely there will be parallel networks to Facebook that could eventually become primary. For instance, if Google had Facebook Connect as a login method, they could quickly assemble the entire social graph and potentially beat Facebook. That's likely why Facebook is in a tiff with Ping - Apple has the capability of replacing Facebook some day.