The new Dungeon Finder tool, promotes the joining of random pugs to receive gold and emblems. There is also an achievement tied directly to the dungeon finder.
When your character completes the “Looking For Multitudes” achievement you will receive this cute little pug as a companion in Azeroth. To complete this achievement, your character must have used the Dungeon tool to group with a total of 100 random players to successfully complete random heroic dungeons. After completing the achievement, you will immediately receive this pet in your mailbox sent by the Blizzard Development Team. Go out there, meet some strangers on the internet and receive a pug.