In the 2.0.12 patch notes, there was a little surreptitious note that seemed pretty tame: "Using the customer support 'Auto-Unstuck' will now trigger the one-hour cooldown on the player's hearthstone." Whenever your character model gets stuck in the world, you can enter the help menu, and choose an "Auto-Unstuck" option that was placed there early in the game's life (so that GMs wouldn't have to come along every time a player got stuck to fix the issue).
What "Auto-Unstuck" actually does is (after a little tweaking to try and get you out close to where you are) port you back to your hearthstone city. I think I've used it once the whole time I've been playing the game. But apparently there was no cooldown on it at all, so what lots of players were doing is using it as a second hearthstone. I knew the possibility was there, but apparently I underestimated players' usage of it-- tons of people were "exploiting" the feature, and now lots of people, both here in America and in Europe, are angry that the hearthstone cooldown is tied to Auto-Unstuck.
If you ask me, it's nothing to get angry about-- the Auto-Unstuck, as Drysc says, is a support feature, and any constant use of it to cut down on travel time indeed "bordered on exploitative use." Players reply that a second hearthstone helped them save travel time (well of course it did), but Drysc says that the devs want the world to feel like a world-- though they've made steps (like Meeting Stones) to cut down on travel, they never wanted players to move around "without any thought to the distance they have to travel."
I gotta side with Blizzard on this one-- they gave you one hearthstone, and using Auto-Unstuck as a second one is against the rules. Some players say that the common cooldown means that if they get stuck twice in the same hour, they're screwed, but that's not necessarily true. A nice warlock could always summon you away, or you could do what one of my groups did to a guy who got stuck in Underbog-- we let him die and then rezzed him back out in the open.