By default the PC version adds the following folders to be shared:  My Documents, My Videos, My Pictures and My Music.

I'm noticing that when I add a bunch of photos to "My Photos, it indexes them and updates the .cedata\cedb file and thumbnail files in the My Pictures folder.  It then indexes them again and updates the .cedata\cedb file and thumbnails files in the My Documents folder.  This is because the My Pictures folder is a sub-folder of My Documents.

I'm not sure what the best practice should be, but indexing the My Videos, My Pictures and My Music folders individually and then indexing them again as part of My Documents is just a waste of processing time and disk space.