Text (SA+errata): {Tap}: Target player exiles a card from his or her graveyard. ; {1}, Exile ~this~: Exile all cards from all graveyards. Draw a card. [Oracle 2009/07/08]
The targeted player chooses which card gets removed by the first ability. [Shards of Alara FAQ 2008/09/23]
The text "remove all graveyards from the game" means to remove all cards in all graveyards from the game. Players still have graveyard zones, but they are empty after this. [Shards of Alara FAQ 2008/09/23]
You can play the second ability even if no player has any cards in their graveyard. [Shards of Alara FAQ 2008/09/23]
