The strange and brutal “dip” just before 16h GMT on January 15, 2007 is some kind of flaw in the counting system of concurrent users online, and has happened several times in the past. Several people noticed it for the first time the day we reached 7 million concurrent users online (see my post "frozen Skype Cloud" on August 29, 2006). Until now, no “official” explanation from the side of Skype*. But it is an erratic phenomenon, because it doesn’t happen every day, although it happens always when a new record of concurrent users online is reached. So let’s discard this phenomenon.
In the “old” pattern of 2005 there are 3 distinctive phenomenons:
- Around 12 GMT there is a dip in the concurrent users online (green curve). The last months this has almost completely faded away (red curve). This could be explained by the strong growth of the American users.
- Peak time was always occurring around 16h GMT. Now, it happens at any moment in the time span 15h to 20h GMT, moments were both Europeans and Americans are using their computers. In the past, Europe was the strongest Skype user continent. Perhaps now it are the Americas?
- The “night dip” was in the past around 02h GMT. Now this dip seems to have risen (proportionally), what again could be an indication that more Americans are still awake and using Skype before that moment.
A better measure would be to calculate the surface below the curve of concurrent users online (see the blue surface in the image on the left). This surface has as unit “users x time” and gives a better indication of the number of users AND the time they stay online.
Therefore i also colored in blue the “gains of relative surface” between the two curves of the first graph. This shows where the Growth of Skype Users is taking place:
- Or indeed American growth
- Or people stay longer online
- Or … both
* there was however yesterday a strange comment of Jaanus Kase on the official Skype Blog, that seems to confirm there is indeed a bug in the counting system! His words after commenting the 9 million concurrent users online milestone: "Next up: double digits in the millions department. I wonder if our testers have actually tested that it will display fine, or will it crash and burn as soon as it hits the tenth million…"