Didn't find any similar threads.
I checked definition on exploits on the intarwebs, and I believe this is the right section to put this in. (exploit - definition of exploit by the Free Online Dictionary, Thesaurus and Encyclopedia.)
This works for both alliance and horde, but it's easiest for alliance to abuse it. I took screenshots of this working, and to show where it was, but after 10 tries uploading the jpg, doublechecking filesize, width and heigth, it still wouldn't upload, so I'll try to explain.
As Alliance: When u jump straight off the mountain edge to get down to the bridge over to D'B only seconds after u've left the cave where u spawn, there is a mountain to ur left. U are now standing where the spirit healer would be if u were dead. If u climb this mountain there is a gap between the two mountains. Stand here, adjust the camera angle so the enemies can't see u, but u can see them, and cast, dot, channel or w/e thru the mountain no matter where the enemy is (as long as he is in range). It's usefull when u're protecting, and hordes come running and u just fear 10 guys without them understanding where u are. (Remember, it works both ways, they can also cast spells thru the mountain at u, but they won't know where u are so the type of spells are limited. I will try to upload again later if this was too hard to understand.
I just discovered it now and im having alot of fun with it, I hope not too many ppl have figured this out allready. Hf