WP7 social integration was copied from Android. Any TW or Sense Android has had this for like 1.5 years before WP7 was released. I didn't use it there, I don't use it here. Good apps are always superior.
Live Tiles = Badges in 90% of cases, Widgets in the other 10%.
WP7 still only has 1/3rd the Notification system of Android/iOS and even then it isn't really consistent even among stock apps (like no Toasts for eMails).
Personally, I think most WP7 device owners are light smartphone users (actually it's pretty obvious at least on the various forums by observing what they tend to not care about in threads addressing the gaps in the platform). As a heavy user (or was, until the HD7 became my daily driver), it's a frustrating time-wasting platform to use and it requires way too many compromises. This is even in comparison to iOS, which shares many of the same limitations and is arguably more locked down than WP7.
A lot of people are moving a lot of activities to their smart devices so they're going from being light users (who can get by with a feature phone, so WP7 is probably a good initial step for them) to heavy users who do a ton of tasks and communications (in different forms) on their devices. I think that's why Android has such a higher "first smartphone" adoption rate, and marketshare as a result.
The only thing refreshing about WP7 is the way the UI is put together, at least at the beginning until you realize the Live Tiles offer basically nothing new that a Badge or Widget couldn't offer and you have to scroll twice as much in applications to digest the same information as on other platforms.
Microsoft needs to do some real usability studies that involve more than them making assumptions or tracking the key presses and activities of fanbois who were ignorant enough to waste battery sending their information from the phone to their data centers (something I almost always turn off immediately when I get a new phone - irregardless of the platform).