Yesterday I saw a post from the Windows Live Messenger team where they said that they recently went over 30 million simultaneous users. Now, lots of statistics are offered up by the major IM networks when referring to their respective audiences, but the two that I like to focus on are simultaneous online users and IMs/day. Claims about "active users" or "total users" can be hard to compare, since it all depends on how you count. Simultaneous users and IMs are clear indications of how many users are stressing the system on a daily basis.
The WLM post got me interested on whether I could determine these numbers for all the major messaging services. A little Googling, and I was able to come up with numbers or reasonable estimates for most of the major services; I've included links to the sources I used. (Google does not release user numbers, so Gtalk is absent from this chart.) Here's the breakdown:
|Service||Active Users||Max Simultaneous Users||Total IMs/day||Dominant Regions|
|Europe, Latin America, East Asia|
|China, South Africa|
|East Asia, Europe|
I couldn't find exact data for some of these numbers, so extrapolated from what I did have. Readers, if you have recent public data for the estimated values (especially Yahoo), I'd be interested to see it.
Nevertheless, from these numbers, it looks like WLM is about as big as Yahoo+AOL+Skype combined. That's a formidable lead in a space that is fairly mature.