There's a feature called "Member Connect" on the Ancestry site. You can choose to be notified if anyone connects to media or other items you've shared. I think you can only view the notifications when you're logged-into the Ancestry.com site, however.

http://community.ancestry.com/memberconnect/

Here are the options for the "activity" you can choose to view (taken from the "Recent Activity Filters" settings box):
-Activity on records I've worked with
-New records, photos & stories added by my connections
-People, facts & sources from my connections
-Existing photos & stories saved by my connections
-Member connections made in family trees
-Other members saving content I've added
-Comments from other members
-Updates to my family tree by people I've invited