The Field Agent Locator (aka Dungeon Finder) allows players from all dimensions to join a queue so other players know they are looking for a group. Players looking for a group are able to specify their role (Healer, Tank, DPS), the dungeon they want to do and the difficulty mode (Normal, Elite, Nightmare) and join the list. Players that are looking to fill spots in their group are able to browse the list and invite you directly through the locator interface!
This addon makes it much easier to find groups instead of being locked down in Agartha spamming the chat channel. Now you can go do your solo missions or socialize with friends where ever you want while looking for a group!