TEXT OF STORY
Bill Radke: Later today, Facebook is expected to announce a new location-based service for users.
Marketplace's Steve Henn says it'll probably use the GPS chip in your mobile phone to track your whereabouts.
STEVE HENN: Marketers dream of slipping into you your pocket with your cell phone -- and following your every move with a mobile app that is always on. So...
JULIE ASK: Facebook does really well in a mobile environment.
Julie Ask at Forrester's Research says Facebook is ubiquitous, easy to use, and millions of folks check it constantly.
But adding a geo-location feature has Jeff Chester at the Center for Digital Democracy worried.
JEFF CHESTER: I think consumers need to be very careful. There are privacy concerns and there are personal security concerns.
And Chester has a host of questions: Will Facebook's users be enrolled in its location service automatically? How will location information be shared or stored? Will folks be able to opt out easily?
He says before people sign up they should take a second and imagine what life could be like if all their Facebook friends can follow their every move as they commute, go for drinks, or even play hooky from work.
In Silicon Valley, I'm Steve Henn for Marketplace.