Copying a Campaign can be very useful - for instance, maybe you want create different Campaigns for different traffic sources so you can track how successful each source is, but you don't want to have to keep manually recreating your winning Landing Page.

From the Campaigns Overview screen ( click the "Configure" button on the Campaign you wish to copy, and then select Duplicate.

An exact copy of the Campaign will be created, minus the traffic and event history.  

Note that the new Campaign retains the Autoresponder settings of the original, but can be changed independently of the original Campaign.