An LBS may inform its users of a traffic jam which might affect many users. A user might be informed of the current whereabouts of his/her friends. Some other LBSs may trace the positions of public transport, hazardous materials, security personnel, police cars, or emergency vehicles. The "catch the monster" game, which is a typical example of more developed LBSs, may allow a set of users to work together, for the purpose of surrounding and catching a geo-positioned monster in the virtual world. Other LBSs may provide mobile users with useful information, e.g., to find an appropriate route in road networks.