Popular check-in application Foursquare is facing a problem that has long bedeviled social networks — spurious friend requests. And it’s dealing with violators by putting a cap on them.

Users now have a limit on the total number of friends they can have as well as the number of friend requests they can send, a change first noticed by AboutFoursquare.com.

For the average user, this may not be an issue: Most users don’t want thousands of people knowing where they are at any given time. So the policy is likely targeted at businesses looking to take advantage of creating a profile on Foursquare. Like Twitter, the microblogging network for posting short status updates, Foursquare allows businesses to create profiles in the same way that people do. That liberal policy is unlike Facebook, the dominant social network, which only allows real human beings to create profiles and requires businesses to use a different format called Pages.

Some companies have been randomly sending friend requests to thousands of Foursquare users, like Bastardjeans.com, which currently has 61, 923 friends. Why would they do this? Well, the benefit comes when one of those users checks in to a venue where Bastardjeans.com has left a tip. Since friends’ tips are displayed first, Bastardjeans.com gets more visibility.

Other advantages include being able to know where these users are from their check-ins, as well as being able to send them messages, since many Foursquare users share contact information with friends. All of these could be advantageous to a business looking to promote itself — though it’s probably not how Foursquare or most of its users envisioned the service operating.

Foursquare CEO Dennis Crowley told VentureBeat that the startup is constantly working to adjust the balance between letting businesses engage with users, while at the same time trying to keep a positive user experience. Asked what the limits on friends and friend requests would be, Crowley said, “I think they’re still in flux right now.”

As of right now, Foursquare’s major competitors, Gowalla and Scvngr, do not have plans to restrict total friends or friend requests.

While Foursquare is still young and most users have few friends compared to the bigger social networks, one wonders if the restrictions may push some avid users to eventually go with another location-based applications with fewer restrictions. That happened with Friendster, an early social network which cracked down on fake profiles and lost ground to the less-restrictive MySpace.

Foursquare, based in New York City and founded in 2009, has raised more than $21 million in funding. It currently has more than 40 employees in its hometown and a new engineering office it’s opening in San Francisco.