Campaign groups help organize your campaigns. You can group campaigns in any way you desire. Perhaps you have a collection of ezine ads, or maybe some banner ads. The purpose of grouping these campaigns is to allow you to create a specific statistics report to display only those campaigns within a group. If you go to the statistics report page you will see that you can select to display the campaigns from your pre-defined groups.
To add a group, fill out one of the forms and press Modify Groups. To delete a group, empty the field of the group you would like to delete and press Modify Groups.