The maximum number of users online goes easily over the 6 million mark on a daily basis, and rarely goes lower than 3 million. The fluctuations follow some pattern during the day. I made some comments on the “why” last year, and repeat part of this later in this article.

I put some red dots in the graph as discussion topics. The first one in 2004 is the launch of SkypeOut, the second one is the eBay day (don’t ask me if this was good for Skype, I would give you only a very speculative answer), and the third red dot in 2005 was the official launch of the video (webcam) feature. I really believe the video feature gave a new impulse to Skype. I see more and more of my 100+ Skype contacts acquiring a webcam and trying it out. In fact 43 % of my online contacts have a web cam. Bill tells me that of his 450 + contacts 35% have a web cam.

The “light blue” data points are numbers I found in blogs and other places from the time before I begun registering myself data.

Well, let’s continue to look at this graph. I plotted the same graph with only the “peak” times. That is that I left out all the points lower then “best week times”. And this gives the next result:

Apparently, holiday periods are NOT good for the growth of Skype. The first period (in the red circle) corresponds to summer 2005, where many inhabitants of the northern hemisphere were on holiday, or drank a beer in their garden instead of sitting in front of a computer. The same is valid for the second red ellipse: this was the period around Christmas 2005 and New Year 2006.

What about the daily fluctuations? Last year I had to use a time consuming trick to follow Skype Users online on a daily basis. And a certain “Richard” pointed out there existed RSS feeds for collecting data on Skype Users online. Although I knew this, my knowledge was limited only to the “knowing”, not to the knowledge how to exploit this. In the coming months I tried to make a macro in Excel to automate the capture of the RSS feeds, but I was never successful.

Then Matthew Rabinowitz, another crazy Skype fanatic and USA citizen living abroad in Germany, begun to chat with me on Skype, and provided me his Excel macro (Windows Professional) he used to capture the RSS feed. I use Windows XP, non-professional version, and his macro didn’t work on “simple XP”. But, by comparing the macro’s I found what was missing in mine. And in the meantime we had some enriching discussions on the growth of Skype.

So, I automated the data capture. Here is the result for the week from Wednesday March 22 to Thursday March 30 2006. Monday 27 was the day Skype broke the 6 million users online (red circle)!

Look also at the two green circles: Matthew pointed out that Sunday 26 was the week-end a lot of countries changed their clock to summer time, and some not. And, you can clearly see the “downward tail” is somehow lower after “Summer Time”. Some people awoke probably at the same Greenwich time, and others an hour later from one week to another! This could explain this minor change in the behavior of the curve.

Like last year, users online have a tendency to go down from Thursday on, with the lowest point in the night from Saturday to Sunday! I speculated that this is the week-end phenomenon: some Muslim countries start their week-end on Thursday, and Christians end it on Sunday. Weekends are indeed bad for Skype (eh, like Holidays!). This seems again to confirm that Skype is mainly used by the working class called “adults”.

Let us pick one day out of this week, March 27, the day Skype reached 6 million concurrent users online:

The shape of the graph didn’t change compared to last year: again a “day – night” pattern mainly centered around GMT+1 because most Skype users are still Western Europeans and North and South-Americans, and there are some moments of the day where both continents are working at the same time! Again a dip around Greenwich Mean Time (GMT) 11h, or 12h (GMT+1), when most European people take a break for lunch. Europeans are still the majority of Skype Users, but I am not really sure my “lunch” theory is correct. I compared the “midday dip time” before summertime, and after (when people changed their clock), and the dip moment stays unchanged around 11h00 GMT. Therefore, another explanation is needed!

The advantage of having automated my RSS feed, thanks to the hint of Matthew, is that I could also make a graph of the downloads of Skype applications during the week. Manipulating the data (in the positive mathematical sense!), gives the following result for the downloads per minute of the Skype application, for the same week around Sunday March 26:

Interesting to see that the day – night pattern is maintained, but not the week-end pattern: as many downloads during the weekend as during the week! And, the mean fluctuates around 350 downloads per minute! Not too bad!

Skype is still growing! Let’s see what the graph looks like in 6 months when the Skype WiFi phone has been released!

And the video feature is really a blessing for me. One of my 3 sons, only 18 years old, left for Brazil some weeks ago, for an undefined period of time: and I can talk and see him at the same time! It makes the distance and the emotional burden (for me at least) bearable! 

(Thanks Matthew Rabinowitz, for proofreading and amending my text)