But to grow to be a cultural phenomenon like , it may need to let those who never check in tap into active users' information, Crowley told the .

Skeptics view Foursquare the way many once viewed . The knock against Twitter was "Who wants to hear what you had for breakfast?" even though the service is considered a serious news-gathering -- and news-breaking -- tool by numerous users, including professional journalists.

Now, some critics of Foursquare say they don't want to know in realtime-- nor do they care -- what locations all their friends are frequenting; others worry about and privacy issues when constantly broadcasting their location.

Proponents, though, say Foursquare offers useful crowd-sourced tips for restaurants, health clubs and the like. Growing a group of users who read and rely on this information without issuing broadcasts of their own would address their privacy concerns.

Crowley said the company has numerous algorithms that help it rank the best and most interesting spots in a city based on data from its millions of users.