January 20, 2008... What percentage of Skype users are online all the time?

Skypenumerology has been speculating on this recently. Back in early November, I actually produced a graph that partially answers the question.

At the time, the maximum concurrent users online had recently reached 10 million and "real users" were 26.3 million. I set out to do a regression analysis of a full day's worth of online statistics, segregating hourly readings for the three world regions. It is possible to do this because of the very obvious inflection points in the graph of concurrent users online. I don't do such analysis very often because it is such a time-consuming and unrewarding process, but presumably a more current analysis would produce similar results.

The result from early November 2007 was the following graph:

At that time there about 2 million concurrent users that I could not assign to any one region. The number of users that were online "around the clock" at that time was therefore LESS THAN about 7.6% of the total "real users". How much less is impossible to know. I also don't know whether this percentage is changing because I've only done the study once. The interesting question, to me, is whether the amplitude of the daily wave is decreasing and whether that decrease is caused by regional fluctuation (such as fast Asian growth) or by growth of 24/7 Skype clients in the mix. I of course agree with Jean Mercier at Skypenumerology that increasing usage by mobile devices will cause the "real users" to rise (and the amplitude of the wave to shrink).