Skype induced or not?

I had some chat discussion with Matthew, US citizen located in Germany, about the phenomenon that we could see yesterday: the dip in the concurrent users online, see my previous post. He pretends this is not "induced by Skype" but, that it is some kind of problem with SuperNodes

On last Saturday, September 23, there was also some strange “behaviour”: during some hours around 14 GMT. The number of downloads, as published by Skype, didn’t rise, see below.

This makes me think that Skype is doing something with its IT systems.

This screenshot is again taken from the Japanese nyanyan.to website.