a system and method designed to reduce network congestion . in one aspect , a system according to the invention includes a server and two or more clients . each client has software that runs on the client . the software requires data that is stored at the server . advantageously , the software maintains a cache for storing the required data after the data is retrieved by the software from the server . once the required data is in a cache , the software need not retrieve the required data from the server ; the software can retrieve the required data from the software &# 39 ; s cache . to ensure that the data that is stored in the cache does not become stale and to avoid network overload , the software updates its cache at a random point in time .