Update: I am working on making this addon work in WoW 6.0, but no luck so far. Huggie (binds /hug and /love for achievements) has been updated and works. This works currently in 5.4 with a TOC update.
This addon allows you to set a key to any emote. OK, this is largely useless, but there are some emotes that are useful (/incoming /attacktarget /charge, etc) and others that can be important for RP. If you're "making a train" it might be good to have /train bound to a key without mucking about with macros.
I've used this to get the chicken pet in Westfall by spamming /chicken about a hundred times, and it makes getting the "Make Love, not Warcraft" achievement in WotLK much easier as well.
1.1_33 only changes the toc file