1. A communications system comprising: at least one data storage device for storing messages for respective users; a plurality of mobile wireless communications devices each associated with a respective user for accessing the messages stored on said at least one data storage device; and an adaptive polling engine for polling said at least one data storage device for stored messages and providing the polled messages to mobile wireless communications devices of respective users; said adaptive polling engine changing a respective rate of polling for each mobile wireless communications device based upon at least one positive polling event and at least one negative polling event, the least one negative polling event comprising a lack of authorized communications.