A telecommunications system includes a plurality of network clients (150) including a positioning controller (504) and a communications controller (502); and a positioning server (152) including a coordinating controller (161) for maintaining a database of network clients to be tracked and provide updates of position-related information to a presence server; wherein said plurality of network clients are configured to transmit position information received via said positioning controller (504) to said positioning server via said communications controller (502), said positioning information including information related to a speed of movement.