Peter Bright:

However, there is still a strong case for further vertical integration. A bunch of hardware companies are on board for the first release of Windows Phone 7, and there will be a range of handsets for sale when it launches. But whether those partners will stick around is less clear. Windows Phone 7 offers much less scope for an OEM to differentiate its products. The custom front-ends that proliferated under Windows Mobile, and are commonplace in the Android world, aren’t an option, and by discarding them, the vendors lose a lot of branding opportunity.