Skype went down for a couple days about a year or two ago, as did a few other voip services at around the same time. I suspect this is more than just a single company that is behind it, rather the US government.
Sure, it's not a secret that the NSA is the one pulling in all of the data they can get their hands on right now. And they absolutely want all skype traffic, since they already have all internet and phone traffic.