I have been a happy and satisfied paid customer at Carbonite.com for several years now. They’ve always had some sort of referral program, but recently it has gotten much better. Previously, if I could get a friend to sign up I would get a couple free months of the service added to my account. Now they offer free Amazon gift cards as a reward. The normal gift card amount is $10 for each referral sign up, but this amount varies as they run different promotions at different time periods. The current holiday promotion they are running is offering a $20 Amazon gift card for not only the person who refers, but also for the person who signs up for Carbonite! Win-Win!