Yeah, but how much would you have to spend to get 500 million users, many of which you already have credit card information for? Not saying this acquisition was necessarily worth the cost at all- but it wasn't just about the technology.
The 500million user figure was from a big TechCrunch article from 2009. http://techcrunch.com/2009/10/21/skype-hits-521-million-user...
Again, I'm not trying to necessarily argue that this acquisition was worth it. But, there is more than technological value here. There is a huge user base here.