Marketing Campaign Codes are used to track where you registrants are coming from when they end up on the Registration page. Using this feature, you can create unique registration URLs for each of the various mediums that you have used to invite attendees.

For example, you can create a unique URL to post on LinkedIn and another for use in your company blog. Once attendees have registered, you can see how many of them used the link via LinkedIn or used the link via the blog.