In exemplary implementations of this invention, data regarding the position and operation of a vehicle is gathered by a GPS unit and an On Board Diagnostic (“OBD”) port, respectively. This data is wirelessly transmitted by a wireless transceiver located in the vehicle. The transmitted data from multiple vehicles is received by a remote processor. The data is processed and selectively shared with users of a public web interface, in accordance with user preferences. A user selects the type of data that may be shared and the specified persons, classes of persons or public with whom particular data or types of data may be shared. In some cases, data gathered by the OBD ports and GPS units is transmitted to a host server of a social network, and selectively shared over the social network in accordance with that network's policies.