I'm looking for a third-party service to integrate with my custom shopping cart to automatically send emails to people that leave the checkout before finishing; aka, abandoning their cart. Basically, anytime someone leaves the site and we have their email address, we'd like to send them an email enticing them to come back to the site.
That's the basics of it, any additional functionality would be great. Suggesting other products, offering some kind of special offer, etc.
I'm just looking for any services that offer this rough description.