The pay rate for endorsing companies like Old Navy, Toyota, Best Buy, and American Airlines is determined by the size of a celeb’s following and how that group responds to his tweets with shares and retweets.
On that sliding scale, Snoop Dogg (6.3 million followers) is in the top tier of payments, on the upside of $8,000 apiece, while Paula Abdul (2.2 million followers) falls somewhere in the middle, in the $5,000-each range, and Whitney Port (800,000 followers) falls in the bottom tier, making around $2,500 per tweet.
But there are outliers. When Ad.ly introduced self-destructing Charlie Sheen to Twitter, he was paid about $50,000 per tweet. ...
Of course Charlie didn’t write those tweets himself. No celebrity does. Instead, they’re composed by hungry young tweet ghostwriters whose job it is to broadcast a celebrity’s voice in 140 characters.
--Jo Piazza, New York, on how some of the rich get richer 140 characters at a time