Forum OpenACS Development: Response to notifications - is there a need for a new package?

I've put up a high-level spec of notifications at

http://dotlrn.openforce.net/doc/notifications.adp

Noting that I am trying to keep things simple for this first iteration, I would like to get people's comments about the direction I'm proposing. I expect to do a very quick first implementation, so the earlier you can comment on this, the better!