Per this Buzzfeed story, Obama, Katy Perry, and Lady Gaga have Twitter accounts which read at the highest grade level of the top ten most followed accounts on Twitter. All came in at around a 6th grade level, which: I have no idea what it means to tweet at a 6th grade level. Is that good? It's tough to demonstrate literacy in 140 characters. To the surprise of no one, Justin Bieber was last, not quite reaching the literacy level of your garden-variety first grader.
Tough luck, Beebz! Stay in school now.