Gates kicked off his speech with

Gates kicked off his speech with a look back at the first digital decade, where the global installed base of PCs grew to over 1 billion machines, broadband rose from almost nothing to 250 million users and how over 40 per cent of the world's population now use mobile phones.

He pointed to software as the driver of many of the digital innovations of the past 10 years,

allowing us to store, organize and share music and photos in a rich way via the PC.

"The trend here is clear - all media and entertainment will be software driven," Gates said.

Gates judged the past 10 years to be a "great success" but said there was nothing holding us back from going "much faster and further" in the second digital decade, which he said would be far more focused on users and connecting them with each other.

Computers would be everywhere - not just on the desk but built into the desk - and people would be able to access their files and applications seamlessly on any device, be it a mobile phone, computer or television.

Many of today's web activities, such as online shopping and online chat, would take place in virtual 3D environments, Gates predicted.

"No longer will users have to bridge between devices ... when you get a new phone or want to borrow a device it will be a very simple thing to be up and running [with all of your files and applications loaded automatically].

But Gates said the most underestimated change coming in the next 10 years was the shift to a "natural user interface", where users interacted with computers using hand gestures.

Gates demonstrated the potential of the technology on the Microsoft Surface computer concept device introduced late last year - a large touch screen table manipulated solely through hand gestures.