I use this all the time...
Scenario:
You are questing in 1k needles. Your hearthstone is set to Orgrimmar. You aren't done your quests, and you want to log out because you have stuff to do in real life, but before logging out you wish to check out the AH at orgrimmar, and do other various tasks there. This bug allows you to hearth to orgrimmar, and hearth you back to 1k needles after your hearth stone's timer cools down. In other words, it's good if you want to log off for more than one hour. This bug is quite useful with Shaman's Hearthing spell.
Instructions
1. Go to the nearest inn (Freewind post in this case)
2. Open up the Innkeeper chat window.
3. Start to hearth.
4. As soon as your about to teleport (When the bar is right near full), select "Make this inn my home."
5. When you teleport to Orgrimmar, your hearth will be set to 1k needles! Check the AH, buy poisons, sell stuff, craft, and then log out. When you are ready to play later, your hearth will have cooled down, and you can go directly back there!