"While there are a wide range of new features in Mango that you'll hear more about in the coming weeks and months, at TechEd we're highlighting a number of new capabilities designed to help you stay productive on the go...Mango is designed to make you even more productive right out-of-the-box - helping you quickly and easily stay connected with the people and information that are most important to you."
There are enough nice improvements that Mango does deserve the .5 release number. Including the email conversation view you see above, there's going to be integration with Office 365 and Windows Live Sky Drive, pinnable email folders, server search, Microsoft's new Lync service, and a bunch of under-the-hood improvements to make WP7 more amenable for corporate IT departments to manage.
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"A planner is a gentle man, with neither sword nor pistol.
He walks along most daintily, because his balls are crystal."