With Phase 2 of the Season of Discovery, Blizzard wants to ban the system of GDKP runs.
We are experimenting with a new policy which will no longer allow GDKP runs in Season of Discovery. While we understand that there are some benefits for those who find this a convenient way to gain gear, we also recognize that there are concerns surrounding the erosion of traditional guild and social structures that are a part of the spirit of Season of Discovery. Given the experimental nature of Season of Discovery, we want to try things without this type of transaction taking place in this game mode. With the launch on February 8, we will be restricting this activity. We will have more information to share on our official channels and will be monitoring feedback closely.
worldofwarcraft.com
GDKP runs are a big topic in Classic. In GDKP runs, players can bid on dropped loot with gold. For example, if a raid boss drops a two-handed weapon, all participants in the raid can bid on it with gold. The raid leader collects the gold and distributes the loot. At the end of the raid, the gold is usually divided among all raid members.