Jeff Blagdon looks at the history of Emoji for The Verge:
But with the release of iOS 5 in late 2011, they made their real international debut. As people found out how to enable the characters on their phones, little pictures of guardsmen and faces with stuck-out tongues started sprouting up all over Twitter, Instagram, and Tumblr.
I never thought about emoji because someone insisted that I enable it on my iPhone. Now I can’t stop.