Cash back rewards are one of the most popular types of credit card rewards, and Discover is upping the ante with a special summer two-month promotion tied to its Discover It card that offers double cash back rewards after the first year of holding the card.

This two-month promotional offer started on June 1 and continues through July 31, 2015. Those who apply for and are approved for a new Discover It card during this time will be able to receive double the cash back on all their purchases for the entire year. There's no limit on the amount of bonus earned through this offer, and the rewards never expire. Cardholders can also redeem the rewards in any amount.

Upon their first anniversary of holding the card, the cardmember will have the bonus cash back applied to their account. Accounts must remain open for the entire twelve-month term, and remain in the cash back program in order to qualify for the deal.

While this special offer targets new customers, Ryan Scully, vice president of marketing at Discover, explained that existing customers could also get in on the extra cash back. "All [existing customers] have to do is call us," he said in an interview. Existing It cardholders can simply call and ask to have the double cash back offer added to their account. Existing customers who don't have the It card can call Discover customer service, have their current card converted to an It card and ask to receive the promotional deal.

"This is a great way for new cardmembers to test drive Discover and experience the generous rewards and industry-recognized customer service,” said Scully in a statement. "These new cardmembers will also enjoy more-recent enhancements available to all of our customers.”

Discover decided to have this special offer as a way of giving its cardmembers what they want. "Something we pride ourselves on is giving rewards," said Scully. Scully added that its rewards contribute to the fact that Discover has received 4.8 out of 5 stars in terms of customer satisfaction and has won top honors in the J.D. Powers U.S. Credit Card Satisfaction Study.

Discover launched its It card in the second half of 2013, and Scully says reaction to it over the last year and a half has been very favorable and that Discover looks at what cardmembers are saying about the product. "We feel very good [about providing] a truly distinctive experience that customers are getting."

Discover has tried to set itself apart is by launching innovative features designed to help its cardmembers to better manage their credit and finances. Scully said it was the first credit card company to give away FICO scores, and it recently launched its Freeze It feature that allows cardmembers to temporarily put a hold on their account if they've misplaced their card. If they find the card, they can unfreeze it and begin using it again, saving themselves the inconvenience of having to close and open a new account. "Everything we do with no annual fee. It's not costing customers anything," said Scully.

The double cash back for one year promotion extends to Discover's full line of It cards, including the standard It card, the NHL branded It card and the student It card. The Discover Miles card is offering a double miles promotion instead of the cash back.

The Discover It card offers a 0% APR on purchases and balance transfers for the first 12 months after opening an account. The APR then varies from 10.99% to 22.99%, depending on the cardholder's creditworthiness.