- probably this concerns only Windows users (not Mac or Linux or others!);
- some people like myself already installed the updates without waiting for Skype;
- some people refuse to install the update.
As suddenly as downloads speed went up, it went down again some days ago. Why? I think i saw the light ;-) due to an almost related comment of "Sugar" on my previous blogpost and due to the duration of this event: exactly 4 weeks. I am almost sure this is Skype induced and most probably it concerns automatic updates of the Windows Skype Client.What can we learn about it? Well, only active users (or real users like Hudson Barton calls them) will get an update. Therefore the difference between the download curve “as it should have been” and “as it was” gives an approximation of the number of active users! From my graph it seems there are 36.7 million active users who accepted to download an updated version of the Skype client.This is really very close to the estimates of Hudson Barton (he uses another estimation method), but it is a lower limit because: