During this week-end, Britain’s Prime Minister David Cameron was busy getting ready to join Twitter, adding to the already very long list of world leaders active on the social web.In a matter of only few days, @David_Cameron has now more than 93,000 followers.He’s following 34 accounts only (UK Members of Parliament, London Mayor Boris Johnson and more to come, we hope!)Cameron’s first tweet was a promise that he won’t overload followers with “too many” updatesDoes that mean that his CM is only part-time ?!