I would love to be able to find where the history is for photos that I have sent from Aperture. I want to send a photo to someone, but don't want them to think I am crazy for sending it twice, so I would love to check to see if I sent it before.
I know there is a way. I saw it once, but I just can't remember how to find it now that I need it.
When you edit metadata views (View Menu > Metadata Display > Customize -or- ⌘-J) that information is in the category “Photo Usage”. Adding it to a view in the Info Inspector is probably the easiest way to see the usage.
You can also search for photos using “Photo Usage” in the Filter dialog.