Guthrie also showed a side-by-side comparison of Windows Phone and Mango for swiping through the Facebook application. In the new version, Facebook loaded faster, while the swipes through pages appeared smoother and also required less memory. In a short demonstration of both versions, the older one used 35MB of memory, compared with 28MB in the new version, a 25% improvement.
Belfiore noted that developing apps for IE9 in Mango won't take as long as it once did, since it will involve the same code used for the desktop version of the browser -- but developers will still have to adapt to the fact that a phone's screen is smaller than a desktop computer's.
"It's the same exact code," Belfiore noted, receiving applause from the audience. "It's not like building one site for both PC and phone, but it's a huge benefit."
Using a Mango phone, Belfiore showed how the new Boston.com site is using HTML 5 video tagging, which allowed him to click for a video clip on the site. "The quality looks great," he noted.
Belfiore also ran an HTML speed-reading demonstration on the Mango phone, next to a Nexus S Android phone and an iPhone 4. The frame rate was the fastest on the Mango device at 26 frames per second, compared with 11 frames per second on the Android device and 2 frames per second on the iPhone.
Another new feature will give users access to developers' independent applications while doing searches in Bing, Belfiore said. In one example, he said a user could use Bing to search for a new movie then jump with one click to related content about actors in the movie in an application called Lmdb.
"We think this idea will help users get more value out of apps," Belfiore said.
Belfiore also said Microsoft is doubling to 35 the number of countries where developers can create apps and where users can buy them. Noting that market research firms Gartner and IDC have forecast that Windows Phone will be the second biggest smartphone operating system by 2015, he said, "we were pretty excited to see our strategy validated, which is no doubt helped by developer support and helped by the Nokia [partnership] announcement."
Marco Argenti, Nokia's head of development, appearing on stage with Belfiore, said Nokia developers are already "working hard" on Windows Phone devices. Noting that mobile billing transactions are growing, Argenti said Windows Phone offers a "great opportunity" for current Symbian developers.
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