Turns out that on Sunday, February 18, at about 19:00 GMT (that's 2 p.m. ET) Skype logged 12 million concurrent sessions for the first time ever.
There's something to be said for the timing of this threshold. Took place on a Sunday. Since few business calls are made during that time, this points to Skype's predominance as a consumer service. I mean, Skype like to talk of their small and medium business relevance, but I just don't see it yet.
Jean also notes that:
In the past the peaks were somewhere between 16h and 17h GMT. Now it occurs about two hours later. This shows a recent growth in the Americas. Or, in other words, they are catching up with the usage rate of the Europeans.