The short version:"If you share a folder, then click the folder to select it, at the bottom of the screen in the details pane, you'll see "State:" and "Shared" with the appropriate "people" icon. It also shows "Shared with" and lists the users/groups."
The long version:"One of the goals for the Windows 7 release is to reduce large cognitive loads on users by simplifying the user interface. With the investment in sharing for the Windows 7 release, and especially with HomeGroup in the consumer space, we believe that a majority of users’ content will be shared. The previous overlay model would have resulted in the sharing overlay appearing frequently in typical Explorer views, potentially distracting users with information that they might not use or need on a daily basis. A single sharing overlay can’t provide details about how an item is shared (for example, who it’s shared with, what privileges are assigned, etc.) and this results in a higher cognitive load for the end user. Prior to Windows 7, there were also scenarios in which the sharing overlay was shown inconsistently, which caused user confusion. As a result, based on the above, the sharing overlay was removed from the items view in Explorer. The sharing state information that the overlay provides isn’t gone but rather has been moved to the Details pane in Windows Explorer. This approach is an improvement over the overlay model, as it helps provide more relevant data related to sharing (for example, who the item is shared with). The Details pane is also where all other relevant properties for an item--such as ratings and author--are displayed, making the overall experience more consistent for end users by providing one location in which they can see all relevant state information for an item.
I hope this helps your understanding of why this changed in Windows 7.
Sincerely,
-Tony Mann"
My head hurts from the "cognitive load" of that explanation!