Disable email notifications if user's address is not valid

[goobertron]

If the email address entered by a user proves to be invalid ('no such address' error), it would be worth disabling email notifications for that account from then on, until the user provides a new email address.

[dmorley]

Your mta would have to backtalk to the app when the email comes back as bad.

I use a hack for this and run bounces from mta to procmail to https://git.feneas.org/diasporg/diaspora/-/blob/master/script/bounce.rb

[goobertron]

Thanks David, that will likely be helpful.