Microsoft and Hewlett-Packard researchers collaborated to write this paper for the Twelfth International World Wide Web Conference in May 2003. The paper looks at the Web as a dynamic entity, constantly changing, and considers how this behavior affects its usability. In particular, search engines are noted as being especially susceptible since they cannot possibly have records of the most current version of every Web page. To measure the rate and amount of change, the researchers "collected 151 million web pages eleven times over, retaining salient information including a feature vector of each page." Their results show which Web page parameters are strong indicators of future change.