This tooltip addon take raid guild ranking data from GuildOx.com and displays the World Rank, Realm Rank and Raid Progression on player tooltips when you mouse over a player. It also works for cross-realm players. It is a great tool to help you assess the expertise of fellow players in a random heroic/battleground or to follow how other guilds on your server are doing with regards to raid progression ranking
The tooltip information shown is "GuildOx World Rank: {worldrank} ({realmrank}) [{progess}]"
The addon is updated on a regular basis to refresh the guild ranking data.