The problem with read notices, much like when we had the unread mail count, is that it creates a stalkerish unrealistic expectation.

Its safe to say that when the person is able to reply, they will reply.  The read notification is simply something that will cause more tension than it could ever possibly benefit the site.

I can't say I will never do it, but, it will be hard to change my mind unless there is overwhelming support for users who want to be tracked and then judged by the sender.