NBC News segment on cell phones embedding location information in photos a.k.a "geotagging".
Others may be able to view this information when the photos are posted online. This is particularly an issue if photos of children are posted online, since it could enable strangers to identify a child's home, school, the park where they play, etc. if photos were taken in those locations and then posted online. The news story also covers how to disable this feature on your cell phone.
Additional information, including how to disable geotagging on many types of smartphones, is available at icanstalkyou.com.