I added the pet emote add-on recently. Just for the heck of it.
EDIT: Most recent version available at Ammunition Company
My official opinion: The pet emote add-on is hilarious.
I think you can edit what it emotes but I haven’t gotten that far yet. So far my pet has randomly sniffled the ground a lot (this cracks my party members up – as not one is sure what sniffling entails, is he smelling something? does he have hay-fever? or is he a whiner pet?)
When I have the cat out it purrs – when I have to wolf out in gnarls and scratches a lot (we all saw the scratching coming eh.) They both gobble when I feed them (pigs.)
I see: “Reaver does blah” on the screen
Friends see: “Fessran’s wolf Reaver does blah” on their screens
You can play with (read edit) the family wording a bit. Of course Cat is a cat called Cat – so his emotes are about as confusing as this sentence.
EDIT Check out Petopia forums for news about PetEmote 2010: http://forums.wow-petopia.com/viewtopic.php?f=3&t=4212&start=0
EDIT Check out the Three Hammers for update on PetEmote 2010: http://forums.threehammers.org/viewtopic.php?f=8&t=1571
EDIT: Efindel & ethancentaurai’s Updated PetEmote addon on Curseforge (FEB 2013): http://wow.curseforge.com/addons/petemote/files/10-v1-8-3/