That makes a nice narrative but I don't think that the strategy made them unstoppable. MySpace had a huge head start and what happened? They got steamrolled because Facebook had better privacy, better design, better performance, and more features. Facebook's secret sauce is its engineering organization. Sure a lot of good ideas went into it, but lots of companies have good ideas, very few have the technical ability (or the balls) to roll them out as quickly as Facebook has.