I'm curious as to what made anyone there think it was a good idea to introduce a new line of phones with a new OS separate from their main phone OS. WP7 seems like it's going to be a hard enough sell already; the smartphone business looks like it's going to be between Apple and everyone else, with everyone else running Android.
I'm guessing that back when the project started it wasn't terribly clear what their main phone OS would even be. Given how uncertain things were, they probably figured letting a couple different teams try a couple different approaches would give them a better chance of stumbling on something that worked.
