Hertz is using its Facebook page to offer a coupon with a twist: The more times a button labeled “share it up”s is clicked, the higher the value of the coupon gets.

The Share It Up campaign runs through April 30, and the discount on the coupon is valid for weekend and weekday rentals from April 16 through July 16.

PeopleString subsidiary Share It Up created its social couponing platform to enable brands to take advantage of Facebook and other social networks and spread the word about their offers.

Hertz Chairman and Chief Executive Officer Mark P. Frissora said:

Hertz is empowering our social media brand ambassadors in an innovative way. Our customers and fans are some of our best advocates, and we are rewarding them, as well as their friends and family.

And Share It Up Executive Vice President Robert DeMeulemeester added:

As the global leader in car rentals, Hertz is demonstrating that social media is about more than gathering fans. We are excited to be working with Hertz to help them harness the power of their fans, followers, and customers to drive brand awareness, loyalty, and sales.

Readers: Would you be driven to share a coupon with your Facebook friends in order to increase its value?