Diablo 3's gold and real-money Auction Houses have been restored and players may resume gold trades, Blizzard announced via Battle.net.
The Auction Houses came back online at 11:10 p.m. ET yesterday. The update notes that Blizzard has also temporarily reverted the gold stack size from 10,000,000 to 1,000,000 in the game's real-money Auction House. Blizzard community manager Lylirra notes that the change has been temporarily reversed to fix a bug currently preventing gold stack sizes from displaying correctly.
Diablo 3's Auction House was taken offline earlier this week after the game's 1.0.8 patch introduced a gold-multiplying bug that allowed players to amass trillions. The bug was fixed shortly after, but the Auction Houses remained in offline maintenance mode for Blizzard to perform a complete transaction audit.
Diablo 3 game director Jay Wilson spoke during GDC 2013 on the game's real-money Auction Houses, revealing that the systems "really hurt the game" and that Blizzard continues to look for a way to fix them.