How are you managing bounces? Have you configured OACS to handle SMTP traffic on port 25? Or is your mailserver running a script which interacts with the database?
I've considered something like this, in combination with an extra header, something like "X-OACS-USER-ID: 12345". Since bounced mail usually returns with the full headers, finding this pattern and flagging something in the db is easier than doing the pattern match on email.
Or are you doing something else entirely?
I'm most curious.
