What is the purpose of the Thumbs Up/Down system?
The Thumbs Up/Down system gives players some, but not complete, control of the maps used during Anonymous Matchmaking play. Any map that a player marks “thumbs down” will not be chosen by Battle.net for a game involving that player. The system also allows us to monitor which maps are popular and unpopular amongst the Battle.net community. This information will assist us when we modify the list of maps available for each game type.