But he does now.
With his younger brother @EdMilibandMP having recently become a twitter enthusiast in his climate campaigning, using the micro-messaging service tonight to break the news that the PM plans to go to Copenhagen, the Foreign Secretary is now open for business at @DMiliband.
Ok this is really me. Off to UN tomorrow. Big week for climate change. Ditto Iran and Middle East. Please send me your thoughts
For those once bitten and twice shy, Krishnan Guru-Murthy of Channel 4 News, whose brother is an FCO staffer who has tweeted "David Miliband is officially on twitter - and it really is him this time" are among those who confirm its veracity.