Valve banned over 40,000 Dota 2 accounts this week and distributed them to players abusing the matchmaking system. The Valve tweet below does not reveal the specifics of the ban, but smurfing seems to be the most suspicious.

Experienced players creating additional accounts to beat up lower ranked players has been a longstanding problem in Dota 2 and many other games that use matchmaking, and the recent ban coincides with an update to the game addressing this issue.

"This update increases the sensitivity of the smurf detection system. This change will allow potential smurf accounts to be targeted more aggressively, but in rare cases may give extra MMR to regular players."

Valve often targets large numbers of smurf accounts, such as the 17,000 we banned last January. These accounts were found to be abusing matchmaking to get ranked; in 2019, the company also introduced changes to how matchmaking ratings are calculated, as well as the aforementioned smurf detection system.

Cheers, Kotaku.