Skype is down. I disagree with Skype’s assessment of the problem on their blog. This is because my Skype was not working at all prior to my logging off. In fact I tried logged off thinking relogging in would fix the problem.
Did they release new software into the network without testing it fully? Who knows, but that would be my best guess.
One of Skype’s best features has historically been reliability. If they lose that, people will likely rapidly migrate to other solutions.