I covered email tracking a little when I wrote about how we parse PowerMTA account files but I didn't go into what we actually do with our delivered / bounced data. We track the current status of an email as: updated, valid, bouncing or invalid. An email address that bounces a certain number of times is marked as invalid. An email address is considered valid whenever we record an email view (via an embedded image) or the member clicks a link we sent them in an email. An email is updated when [...]