Emojili, a new emoji-only social network is now accepting reservations for usernames. You can find TMO's own Jeff Gamet there, and myself as well. Oh, and Bryan Chaffin, too. Jeff's username involves throwing shade at pants (natch), and mine is the hand pointing left and an apple.
Jeff (top) and Kelly (bottom)
Emojili's site is a bit light on information, at this point consisting of a single page with a one minute video. All they say now is that your username must be emoji.
It sounds as though all communication will be in emoji, or if it's just usernames, but maybe it'll be easier to dodge spambots since typing emoji on a computer is slightly more complicated than on an iPhone.