Valve has announced a number of major changes to Dota 2′s matchmaking, most notably an all-new feature that would require players to link their phone number to their Steam account in order to play ranked matchmaking.
According to the post on the Dota 2 Blog, the developers hope that this change will cut down on players using multiple accounts and lead to a more positive matchmaking experience at all skill levels. Players will have until May 4th to register their numbers, at which point any account without a linked number will be ineligible for ranked play.
In addition to phone number linking, Valve is bringing back solo queue along with an option to only match against other players that are queuing alone. In the past some solo players would occasionally be placed in matches with teams to speed up the matchmaking process, but now players can choose to opt out of these games.