NEW YORK - Foursquare Labs has reached its 10 millionth registered user this week and it also announced a national agreement with American Express to offer cardholder discounts, the New York Times reports.

The social media platform will give discounts when AmEx cardholders check in via their cell phones at stores and restaurants. Currently, Foursquare users get coupons or digital merit badges as rewards, but the American Express partnership will create a more substantial discount.

Last month, a Pew Research Center survey revealed that 4 percent of American adults used location services like Foursquare, which are more popular in urban areas. "In 2010, it was all about the check in," said Noah Elkin, a mobile industry analyst with eMarketer. "Now, it??s about checking out."

The Foursquare-American Express deal will not financially benefit Foursquare, but the location service hopes the promotion will bring in other partnerships and raise its profile.

Deals offered first will involve H&M and Sports Authority and some New York restaurants. "We??ve always done marketing with merchants to make offers to our card members, like send offers through direct mail, put information about sales on the Internet," said Edward Gilligan, American Express vice chairman. "But those response rates tend to be low."