In previous versions of Windows, an overlay was applied to folders icons in Windows Explorer to indicate that they were shared. In Windows XP and earlier, this overlay was a hand; in Windows Vista it was two people. Beginning with Windows 7 however, no overlay is displayed on icons of shared folders in Windows Explorer. How can you tell then whether a folder is shared or not?
Simple—select a folder in Windows Explorer and look at the details pane at the bottom of the Windows Explorer window. If the folder is shared, you'll see "State: Shared" with Vista's people overlay icon. You'll also see "Shared With" and a list of the users/groups the folder is shared with, which is handy as it means you don't have to open the properties sheet of the folder to determine the scope of sharing.
Mitch Tulloch is a Microsoft Most Valuable Professional (MVP) and widely recognized expert on Windows administration, deployment and virtualization. For more tips by Mitch you can follow him on Twitter or friend him on Facebook.