A system including: a system control unit; a context aggregator operatively connected to the control unit, where the context aggregator is configured to on predefined events, receive context information about a user from two or more context sensors, calculate an aggregated presence status for the user based on the received context information, wherein a classification algorithm is used to calculate the aggregated presence status; and a user database operatively connected to the control unit, wherein the user database is configures to store user information for plural users, the user information comprising at least a user name, the aggregated presence status, available communications terminals and a probability of reaching the user on each of the available communication terminals, wherein the available terminals and their probability is a function of the aggregated presence status, wherein the system control unit is configured to, on demand distribute at least parts of the user information, including the available communication terminals and their probability, from the user database to a requesting device or application.