1. Richard Branson, Tycoon
An unexpected and, to some of our panel, controversial number one, the founder of Virgin Group (or "the smiley man with the beard", as he's styled on his blog) is a bigger force in social media than many people realise. Already an investor in Twitter, Branson has recently put funds into blogging platform Tumblr and into Twitter founder Jack Dorsey's new mobile payment scheme, Square. And in the past year he seems to have devoted increasing energy to making a name for himself in the Twittersphere.
His first tweets appeared in 2008, reassuring the public about his safety during his unsuccessful record attempt at sailing east across the Atlantic. These days he holds forth more frequently, on a range of issues, from Russian drug policy to office romance, cervical cancer campaigns and advertising for crew for Virgin Atlantic.
Hardcore Twitterati may be alienated by the corporate nature of some of his output, and by his reluctance to reply to his followers' comments.
But the warm, blokeish, man-of-the-people persona that has served him so well in the past has clearly struck a chord on Twitter, and no one can accuse him of ignoring the wider world. Recent themes include the decriminalisation of drugs, the democratic deficit in the Maldives – and a campaign for condom machines in ladies' lavatories. His 1.8 million followers retweet him avidly, and when Branson takes up a cause the effect is considerable. He is also recurrently enthusiastic about the doings of his family, and about his ambitions to travel in space.
Branson is bound to be gratified by his No 1 ranking. During a recent Twitter Q&A he was asked what the biggest regret of his career was; he replied: "Not starting Twitter."
Tweets as: @richardbranson PeerIndex: 93 Authority: 95 Activity: 46 Audience: 97 Follows: 6,414 Followers: 1,834,516Follow @richardbranson