Google on Tuesday began letting smartphone users check into spots on the go as the Internet star jumped into the hot location-based services arena with Facebook, Foursquare and Gowalla.

The check-in feature was added to a Latitude service that lets people with GPS-enabled Android smartphones share their whereabouts with selected friends.

"You can still use Latitude to automatically update and share your location, but check-ins let you add context to the location, like captions to a photo," Google software engineer Joe LaPenna said in a blog post.

The new Latitude service works with a 5.1 version of Google Maps for devices running on Android software.

Unlike other smartphone check-in services, Latitude can use satellite postioning capabilities of handsets to automatically update where people are, according to LaPenna.

"You can talk to friends or finish your bagel without fumbling with your phone," LaPenna said. "Once you leave, Latitude knows to automatically check you out of places so friends aren't left guessing if you're still there."

Location-sharing service Foursquare last week announced that its ranks grew by 3,400 percent in the past year and that it now has more than six million registered users.

Foursquare and rival Gowalla let people log their locations by "checking in" from where they are at any given moment using smartphones or other Internet-linked devices.

People's whereabouts and text comments, if any, are then shared with selected circles of friends.

Facebook last year released a Places and Deals applications that let members use smartphones to share their whereabouts with friends and get rewarded with notifications regarding deals at nearby shops or restaurants.

Facebook Places marked the firm's first step into location-based services that have been catching on with the popularity of smartphones.

Location-based services have proven potential when it comes to targeting advertising or promotions that users happen to be near.