I havn't seen this exploit mentioned anywhere on the forums, so gonna post it, sorry if it's already been posted, but i havn't seen it anywhere
So, the idea is that you can see if a player of the opposing faction is online at the moment.
lets say you got ganked alot of times by a player we call "Hydro" and he always gank in Un'Goro Crater, and you wanna see if he's online or it's safe to go to Un'goro.
Simply type: /ignore Hydro if the player is online, he will get on your ignore list (even tho he's of the opposing faction), If he's not online, it will simply say "Player not found."
Don't know if it's an exploit, but i have had good use of it to see if the local gankers were online or i could go level in the areas they reside.