Days after launching Windows 8, Microsoft is mounting a strong campaign to win over the software developers it needs to kick-start its new operating system.

A lack of apps is Microsoft's Achilles heel as it attempts to catch Apple and Google in the rush toward mobile computing.

"With the work we have done with Nokia, HTC, Samsung and others, I think really there is now an opportunity to create really a strong third participant in the smartphone market."

"There is a lot of work to do, the is a lot of work to do to get applications built and that means a lot of opportunity for people in the room today, there is a lot of work to do to really get a full set of devices in the market and get those to be broadly available, but the foundation is certainly there."

"We're still relatively small, but I would tell you that the level of innovation and the quality of the new Windows phones that you will find on the market is absolutely unbelievable and I expect the volumes on Windows Phone to really ramp quickly."