Facebook has grabbed Hot Potato, a young Internet firm that lets people use smartphones to let friends know what they are up to at any given moment.
Hot Potato informed fans of the takeover on Friday; just two days after Facebook threw the switch on a new feature that lets US members of the social networking service share their whereabouts with friends while on the move.
"We're excited to confirm that we recently acquired Hot Potato, a service that helps people socialize around live events and share what they're doing with friends," Facebook said in an email response to an AFP inquiry.
"We've admired for some time how Hot Potato is tackling this space and look forward to working with them to bring Hot Potato innovations to Facebook."
Hot Potato about eight months ago launched a social networking service that lets users "check-in" to let friends know what they are thinking, watching, playing, attending, listening to, or otherwise doing.
Hot Potato's approach distinguished it from the growing field of location-based social networks such as Foursquare and Gowalla that let people check into places such as a specific restaurant, park, or theater.
Whereas Foursquare might let people know a friend checked-in to a local pub, Hot Potato prompts users to complete thoughts including "I'm listening to" and "I'm thinking."
The Hot Potato approach is reminiscent of a private-circle version of Twitter, the hot microblogging service that lets people share thoughts and moments at any time in the form of terse text messages.
"Since going live last November, we've been inspired and energized by your reaction to the service and people's appetite for socializing around activities and live events," the New York City-based startup said in a blog post.
"If Hot Potato was going to sell to anyone, Facebook was the natural choice."
The startup told members how to download their information from the website and said it will delete all user data when it closes shop in about a month.
The acquisition appeared to be another step in a vision by Facebook to become a collective memory of sorts, letting members tie their experiences and thoughts to locations for posterity.
A Facebook Places service that began rolling out in the United States on Wednesday marked the firm's hotly anticipated first step into "location-based" services that have been catching on with people who own smartphones equipped with satellite position tracking capabilities.
"You can immediately tell people about that favorite spot with Facebook Places," said Places product manager Michael Eyal Sharon.
"You can share where you are and the friends you're with in real time from your mobile device."
Facebook members can "check-in" at restaurants, bars, or other social venues and let their friends at the social network instantly know where they are and with whom.
A Places application for iPhone handsets was released, and social network members with smartphones with Web browser software that supports geo-location and HTML5 could use Places at the mobile website touch.facebook.com.
Privacy advocates were quick to express concerns about adding people's whereabouts to the treasure trove of personal data Facebook users store at the social-networking service.
"We understand and appreciate the various privacy protections and options that are currently available to Places users," the American Civil Liberties Union said in a release.
"But there were some straightforward steps that we highlighted to Facebook that they could have taken to improve the privacy features before launch."
Explore further: Facebook checks in, adding location-based feature