In a lecture delivered at London's Banqueting Hall, Mr Duncan outlined plans "to build on what Channel 4 has always done - stimulate, infuriate, debate, create."
"The difference is we're doing it in many more ways than just via broadcast these days, because we have to engage with the public wherever they are," he added.
Catch up
Channel 4 already offers a pay-per-view service through a deal with Disney which allows viewers to catch up on US programmes.
The broadcaster will carry the same adverts as on TV but has plans to sell advertising space in the future.
The BBC is currently showing live World Cup games to UK users and also has plans to simulcast shows on TV, radio and the internet.
The programmes will then be available up to seven days after they have gone on air.
ITV recently announced that they would soon be able to show programmes on any platform, including broadband and mobile phones, up to 30 days following their first transmission.