Is Facebook taking over the world?

I'm only a light user of Facebook, and reserve it for family and close friends. It is interesting to watch the evolution of other social media sites like Twitter and LinkedIn, which month by month continually add features and interface tweaks to bring them closer to a Facebook look and feel. This is neither good nor bad, and makes a certain sense since what we are seeing is the evolution of a certain approach to interface design, in the context of social connectivity. But what is likely to start appearing is Facebook-style interfaces tacked onto other kinds of services and Web sites, and some of those interfaces won't actually work very well.