As we reported earlier this week, Blizzard took down the Diablo III gold and real-money auction house after a new gold duping exploit was introduced with the recently released update 1.0.8. Blizzard posted a new update today to let players know that the process of reviewing the individual accounts of those that used the exploit is taking longer than expected, so the auction house will remain under maintenance for at least the next day, perhaps longer.

"As we mentioned earlier, we're currently auditing transactions that were performed on the both the gold and real-money Auction House following the gold exploit in patch 1.0.8 that was discovered on Tuesday. We decided to perform a complete audit and focus on the few players that exploited this bug rather than performing a full rollback and taking everyone offline for a day – losing all the progress they made.

This audit is a time-intensive process, and to make sure that we can do a thorough job, we’re going to keep the Auction Houses in maintenance until that work is complete. Unfortunately, our previous estimate was incorrect, and for that I personally apologize. We don’t have a new ETA, but we anticipate that the service will be unavailable for at least another 24 hours. We’ll continue to provide updates in this thread regarding the status of our Auction House maintenance as they become available."

Source: Diablo III Auction House Update