Bring Socrethar's Teleportation Stone to Voren'thal the Seer at the Scryer's Tier in Shattrath City. Completing quests for the Scryers will cause your Aldor reputation to decrease.
Now I can properly send you back to Shattrath City. You've uncovered evidence of Kael'thas making pacts with the Burning Legion and you've got the key to the overlord's back door.
Make sure Voren'thal doesn't topple over with excitement from the news - the old man's getting a bit fragile, if you know what I mean. You'll find him inside the Seer's Library at the Scryer's Tier.