“…In measurement literature, the majority of effort was spent on the behavior of web pages, including analysis of server logs [27], page-modification frequency during crawling [2], [4], [17], [24], RSS feed dynamics [34], and content change between consecutive observations [1], [14], [26]. Problems related to estimation of F U (x) have also emerged in prediction of future updates [5], [6], [13], [18], [31], [38], with a good survey in [25], and user lifetime measurement in decentralized P2P networks [3], [33], [37], [40].…”