It spans the universe.
No city in Azeroth can do what the Exodar can. Repaired at last, the Exodar is no mere fortress but rather a satellite of the great Tempest Keep brought to Outland by the naaru. As a result, the Exodar possesses the power to bridge the gulf between worlds, traveling through the Twisting Nether. And after years spent crashed into Azuremyst Isle, the Exodar is fully operational.
But in her turn, the Exodar is more than a vessel. The means of escape for Velen and the draenei who survived the assault of the blood-maddened orc butchery that reduced them to hiding in Zangarmarsh, the Exodar carried them forth after it had been liberated from the blood elves who had invaded Tempest Keep proper. Sabotaged by those same blood elves, servants of Kael'thas Sunstrider, the Exodar's crash landing was yet another travail for the draenei to overcome. But on Azeroth, they found a refuge from the Burning Legion and the will to move forward as members of the Alliance.
It was to the Exodar that Prince Anduin Wrynn of Stormwind came to study the way of the Light under Velen, and in so doing, in time introduce the draenei way of viewing the Light to the Eastern Kingdoms. It was at the Exodar that Velen pledged that the draenei would not leave Azeroth to fend for itself but would stay and defend their new home.
The Exodar spans the universe, right from where it sits today.