Google Spreadsheets has a great feature for notifying you when another document collaborator makes a change to the document.
However, you will notice on all other document types (Documents, Drawings, and Presentations) that the option for Notification Rules is not available.
I initially thought this was an issue with my share settings or something I was not configuring correctly, but as it turns out, this really is just a feature available in Spreadsheets at the moment. I expect Google will deliver this feature to other document types soon.