As Dota 2 consistently racks up new content updates, it seems like fans have been racking up big numbers for Valve in terms of overall playtime. Breaking the record for overall concurrent players for a Steam game set by Skyrim (287, 411), Dota 2 now boasts the title of the most popular game on Steam ever with 297,116 concurrent users.
For reference, it is free, and people could easily get a free beta code, but the game isn't even officially out yet, and go only go up from here as more content is added. 297,116 concurrent players is still nothing to scoff at for a MOBA.
If there was ever any doubt in people's minds, Valve does it again!