My friend who worked at Skype at the time tells me the rebuild was because of the rise of mobile devices, and the limitations of mobile internet at the time. Sk

My friend who worked at Skype at the time tells me the rebuild was because of the rise of mobile devices, and the limitations of mobile internet at the time. Skype's original architecture used peer to peer routing, ie network quality relied on there being always-on nodes in between the calling parties. Demand for mobile Skype grew, but no one wanted to use their expensive, limited bandwidth mobile internet to be a router in the Skype network. Not to mention, those mobile connections weren't stable enough to be useful for nodes anyway. Hence the redesign around a client-server model, where MS could guarantee call quality a lot better, and which allowed for mobile to thrive. None of which excuses the UI of course, or problems with the back end. Or lync, or any of the other problems. But it does give some context.