ou’ve worked your ass off to fill the top of the funnel, so you better ensure that your funnel is as water tight as possible. When a user expects the slightest bit of interest in signing up, capture their e-mail address. If they don’t finish the signup process within a reasonable amount of time, message them! Save their contact information to a marketing list, dedicated just for people who haven’t finished. For a while, you should even consider having the system e-mail your team as well, so you can reach out to them directly. Believe it or not, this has lead to some great conversations as well.
Can I just say that this is an example of what not to do? If I choose not to sign up for your service, sending me e-mails begging pretty please isn't going to magically change my mind. If anything, it'll make me less inclined to recommend your service to someone else (as well as me putting your e-mail address into an auto-trash filter).