1. A computer-implemented method, comprising: monitoring, within a dynamic page generation system, dynamic page generation events associated with a set of one or more Uniform Resource Locators (URLs), said monitoring comprising maintaining statistical data regarding how frequently the dynamic page generation system performs particular content retrieval tasks as part of the dynamic page generation events; generating, based at least partly on the statistical data, a mapping table that maps the set of one or more URLs to a set of content retrieval tasks, the mapping table identifying, for a first URL in the set, a plurality of content retrieval tasks previously performed by the dynamic page generation system to retrieve content used to dynamically generate corresponding pages, said mapping table stored in computer memory; and responding, by the dynamic page generation system, to a page request from a user computing device by (1) determining that the page request corresponds to the first URL, (2) using the mapping table to identify and preemptively initiate the plurality of content retrieval tasks to predictively retrieve content for dynamically generating a page in response to the page request, (3) dynamically generating a page in response to the page request, wherein dynamically generating the page comprises determining which of a plurality of items of the predictively retrieved content to use to dynamically generate the page, and (4) transmitting the dynamically generated page on a network to the user computing device; said method performed in its entirety by a computing system that comprises a server machine.