Origin is apparently close to 40 million users using the platform.
The number is taken from both the PC platform and the iOS platforms. That being said, EA didn’t disclose how many of these 40 million are actually active. So far the platform holds about 500 games from both EA and other partnered publishers.
In October 2012, the platform held about 30 million users.
Yesterday (February 8th), the Origin client went live for Mac users. The alpha build of the client launched in January for selected users. There’s not a whole lot of games available, only about 50. Most of these seems to be The Sims 3 and the various expansions to that game. Dragon Age 2, Batman: Arkham Asylum/City, and various Lego games have all popped up.
The Mac client really doesn’t differ much from the PC client. One thing that EA is doing right is that they’re offering ”dual-platform play”. If you purchase a game to either PC or Mac, you can play that on the platform you didn’t purchase it on. You won’t be charged twice. It all depends on whether or not the game is available on either platform, of course.