A little tip for using iOS emoji in OSX Messages
I may be joining the party quite late but, until tonight, I did not know how to use iOS style emoji on my Mac. It's quite frustrating being used to the emoji keyboard selection on my iPhone or iPad and then not having it when I switch over to my computer. Yes, the Messages app has the little smiley face icon in the lower right hand corner, but those are not the same—quite lame really.
So, when you're typing in the text box, press: Cmd+Opt+T (or go to Edit > Special Characters)
This brings up the Character Palette. You'll see Emoji listed on the left. Just double-click on the symbol you want to add. Of course, why these emoji don't just replace the existing ones in Messages is beyond me.