On irc we've been discussing how to implement the history feed in our nymap spec - http://www.openplans.org/projects/opencore/maps-part-1/map_large05.jpg
I think I may have a much simpler way to do it, so that we can get the full history feed with a simple GetLog request.
We insert all relevant information as the 'commit comment' when the openlayers client does the insert. The commit comment was made to the meta information that the client wants people to know about the revision. This actually can directly give us really good granularity, because the client will know if an update is to move a note, to update a note, or creating a new note. And the client can record exactly what feature was editing. Which for this case is easy, since people only change one feature at a time.
So basically if the insert and update code includes the featureid of the object (note or comment) changed, and whether it was updated, moved, deleted or inserted, then the GetLog should return all the relevant information needed for the history feed. The author and timestamp are already part of the GetLog request.
Unfortunately I have no time to follow up on this, but discuss and maybe try it out?
Chris