Mayor Michael Bloomberg

Most people know that New York Mayor Michael Bloomberg was a billionaire mogul long before running for office, but many of them overlook the fact that the cash originally came from tech innovation, namely founding the financial services software company that would revolutionize the spread and exchange of information on Wall Street and beyond.

The Silicon Alley Insider put Bloomberg at the top of its inaugural list of influential tech leaders in New York in 2007. Indeed, in office he has embarked upon ambitious green-tech projects involving everything from wind farms on top of skyscrapers to hybrid taxis, given his stamp of approval to several of the city's collaborative workspaces where many new tech company ideas are hatched, and debuted a tech VC fund. What's next for him on the tech front? We'll probably find out during the city's second annual Internet Week New York in June.

Bloomberg, who originally ran as a Republican but dropped his affiliation in 2007, has been mayor of New York since 2002 and plans to run for another term this year.