At a developer conference in Japan, Steve Ballmer gave an actual number for the upcoming features in Windows Phone 7.5 "Mango": 500.
"We've a release that'll come to market later this year -- not only is it a new release that's much more global, but we've added over 500 new features to Windows Phone," said Ballmer. "That information will be forthcoming, including some of the particulars about who's going to be building Windows Phone and which carriers will be offering them in Japan."
Mango also is expected to include the ability to make homescreen "tiles" out of any application feature or page.
"We're pushing for a different approach to user interface design, an approach which -- literally right on the homescreen of the WP -- you, our developers, can provide integrated experiences across your own and third-party apps that're alive and vibrant and real time for our joint customers," said Ballmer.
Other expected features include IE9, Angry Birds app (pushed back to June 29), and a host of productivity-enhancing business tools.
Ballmer also addressed Microsoft's $8.5 billion acquisition of Skype.
"Skype is the most popular software on the planet for people who want to do real-time video connections," he said. "And we want to connect that up for business and consumer to all parts of the planet and continue to transform the future of communication."