As was revealed in an announcement on the forum

As was revealed in an announcement on the forum

World of Warcraft 's WoTLK Classic Gold Next Patch is expected to bring Auction House Changes And A New Trade Channel

World of Warcraft 's next patch will include two major modifications to the way certain goods and services are offered in Azeroth, introducing region-wide commodities and a brand-new trade channel.

As was revealed in an announcement on the forum, patch 9.2.7 that is currently testing on its trial realm will render selling consumable items like herbs, gemstones, and potions through the in-game auction house a all-regional affair instead of the server-specific version. Blizzard mentions that how the auction house functions or looks will not change, but that the region-wide changes will lead to "way increasing the number of buyers and sellers" for certain items. A lot of other items, including armor and weapons will remain server-specific.

It's a significant shift for the economics of WoW that has traditionally been specific to servers. Server-specific economies have allowed dedicated players to take advantage of the market, which is significantly more difficult to do now that players will need to compete with all servers in their region. However, the change should be a benefit for smaller servers that don't have many goods and consumables to choose from in their servers-specific marketplaces. The most recent major overhaul to the auction house in WoW came in  buy WOW WoTLK Classic Gold 2020 during the Battle for Azeroth expansion, in which Blizzard overhauled auction house's user interface.