Incomplete registration email is one of the best marketing ideas that I have ever seen. Often people start to register for something on a site, and then for some reason stop. There is an answer to that to possibly bring your potential customer back, with event organization software you can see the information that the person started to enter, and have the software automatically send out a letter pertaining to the subject. For example, if you are trying to get people to register for something rather expensive, you can set this software to send out an email to a person who started to register, with a 10% discount on whatever it was. You can customize it however you would like!