大象传媒

Barack Obama tweets, Britney Spears tweets, and all the climate change crowd at Copenhagen are tweeting madly too. Twitter, the micro-blogging website is all the rage. In the last year it has become a cultural phenomenon, with millions of individuals and more and more governments and companies using it. All this comes, free of charge to the users.

Despite its huge success and high profile, Twitter is a business that has not yet made a profit. It has now made financial deals with the search companies Google and Bing. Twitter co-founder Biz Stone talks about its strategy to find earnings. And will Google use material from Twitter to target users with behavioural advertising?

We hear about Selco, a social enterprise working to bring solar-powered light to India's rural poor.

Plus, the lobbying efforts of energy companies before the Copenhagen climate change conference. The International Consortium of Investigative Journalists says there are five lobbyists to every member of the US Congress.