Also, even if you do use search, if it doesn't find a game by a specified amount of time, it will start hosting and periodically go back to searching for a bit. Search seems to be the better choice for finding a game at the moment, but host is useful if you are coordinating with someone to join your game, for instance to help an apprentice with a merged/epic/pauper/tournament/singleton/mixture of the previous match since it defaults to standard matches when you invite through friends/apprentice/master list.