It takes you back to your hearthstone point. It's actually pretty abusable as a free hearthstone, unless they changed it so it triggers the cooldown.
I hit level 26 on my shaman using up his rest bonus (I like to do that since iirc it caps out at 1.5 or 2 levels or so, and I had a full level of it) and have been enjoying the class, though it's changed a lot in minor ways since I played it in beta. Warlock's still at 52, finally learned gnomish engineering, and can't get allakhazam to update his profile. I got a really sweet green lens of stamina (+35 stamina total) that I'm wearing now and the gnomish net-o-matic and battle chicken (which is hilarious AND deadly) in my trinket slots, plus some extra engineering headgear for situational uses (catseye goggles for dealing with rogues, druids and night elves, gnomish mind control helm for whenever I actually don't have a pet and want to mess with someone). Also trying to skill up so I can learn the thorium rifle schematic, which I picked up last night (it isn't the best gun, but it's one of the best crafted ones). As buggy as my warlock is, I'm enjoying it. Though I'm not enjoying the 15g talent reset fee I may have to pay when I hit 60 to respec either for the ruin talent from destruction or go heavily destruction and minorly affliction/demonology. I've found that affliction is the best solo talent tree and decent at grouping (though I find immolate is a lot better DOT to use than corruption) and destruction is better at grouping and decent at soloing. With fear kiting I can kill same level elite mobs, but I'll pretty much not be able to solo once I get to the plaguelands due to all the undead (meanwhile, blizzard's favorite god class, the paladin, is only even better in plaguelands). I just hope there's a better fucking use for a warlock in scholomance/stratholme than soulstones and sustained dps that only really works against named mobs/bosses. I don't want to be tagging along uselessly on guild groups just to collect the dreadmist set (which is my ultimate goal with my warlock).