The Japanese author of the graph made a short explanation (in English) on his blog (click here).
He tells us he has two sources:
- the Skype RSS feed (see a link on the right side of my blog)
- the Skype client "people online" information
I will publish here my thoughts about Skype, and mainly about the "numbers". Indeed, as a first hour user, since almost the beginning of the exponential growth i tried to register some data about it. I published in the past as a Guest Blogger in Skype Journal and Skype News some graphs and comments and will continue this here.
English isn't my mother tongue: corrections are highly appreciated!