My bad - I should have been clearer.

This wasn't in the systray/notifications area. In 11.10, on the left end of the
Unity application bar, I had the following: File, Edit, View, Go, Bookmarks,
Help.

Bookmarks was the drop-down menu of my user-defined nautilus folder bookmarks.
It's still there if I'm actively using nautilus, but in 11.10, nautilus wasn't
even open - those bookmarks were just always available on the desktop
applications bar - very handy and convenient. I don't remember tweaking
anything to get it there, but that's also a possibility.

In 12.04, it's gone. Ideas?