Lo explican en Ars Technica:

The real-money auction service was originally planned to launch a week after the game’s May 15 release, but the rollout was briefly pushed back to a planned May 29 before this latest delay. Blizzard now says that it «need[s] a bit more time to iron out the existing general stability and gameplay issues» in order to «ensure everyone has the smoothest experience possible» with the service. While the company didn’t suggest a new date for the launch, it did promise to have «more information soon.»

Con la gracia que me hizo enterarme de la inclusión de esta tienda tras leerme la muy recomendable Reamde de Neal Stephenson, en la que el plot parte de una idea similar.