Not to bring down the general caliber of academic discussion currently going on here at Terra Nova, but :).
I recently wrote a feature for a new Village Voice Media pop culture blog I co-anchor called "Top 10 Emoticons for Flirting Online with Minimal Effort." Silly though the piece may be, it brings up some hopefully interesting points about the shifted meanings of what appear to the untrained eye as simple ASCI faces. Much like the socially normalizing LOL, which can supposedly save the dignity of even Second Life players sitting naked in their lawn chairs, emoticons take on new, adapted meanings in online, multiuser environments.
Any additional meanings to add?