American Express Co. cardholders can now redeem their Membership Rewards points to buy virtual goods under an agreement the New York card company announced this week with social-game developer Zynga Inc.

Amex cardholders also may use points for physical and virtual game cards for Zynga's games, which include games on Facebook Inc.'s social networking site, including FarmVille, CafeWorld and YoVille.

The deal makes it possible for the first time for cardholders to redeem reward points for virtual games and goods, Amex and industry observers say.

Cardmembers may buy limited-edition Zynga goods such as FarmVille manors and windmills, Café World fountains and stoves, and YoVille roadsters and robots.

Specific redemption offers start at 200 points. Consumers may use Zynga game cards for multiple games, including FarmVille, FrontierVille, PetVille, YoVille, Treasure Isle and Café World.

Amex may be making a good strategic move by adding virtual goods to its redemption options to capture the young-adult market, which includes fervent users of social-media networks such as Facebook, one analyst says.

"This is a really smart way for the traditional payments industry to get involved in social networks to attract younger people," says Megan Bramlette, a director with the New York payments consulting firm Auriemma Consulting Group.

"This virtual-economy thing is a very real market force because billions of dollars are being spent in these virtual economies," Bramlette said. "It's not something to be discounted."

Amex plans to expand the redemption offers on Dec. 6 to include 20 more types of virtual goods, including FrontierVille Fancy Gold Hot Tub and FarmVille Golden Retriever.