1. A system for facilitating digital tag prefetching, the system comprising: a computer system comprising physical computer hardware configured to: request a first content page of a content site from a content site server, the content site comprising the first content page and a subsequent content page, the first content page comprising first page elements and an embedded reference to a first tag, the subsequent content page comprising second page elements, the first tag comprising first instructions for gathering first data indicative of user interactions with the content site; load the first page elements in memory of the computer system to cause the first page elements to be rendered for output on a display to a user; load the first tag in the memory; execute the first tag with respect to the first content page to cause the first data indicative of user interactions with the first content page to be gathered and transmitted over a computer network to a remote processing system; prior to loading the subsequent content page in the memory, prefetch a second tag related to the subsequent content page, the second tag comprising second instructions for gathering second data indicative of user interactions with the content site, wherein the computer system is configured to prefetch the second tag by at least: requesting the second tag from a tag server over the network, and caching the second tag in the memory for later execution with respect to the subsequent content page and not executing the second tag with respect to the first content page; and in response to loading of the subsequent content page in place of the first content page, execute the second tag with respect to the subsequent content page to cause the second data indicative of user interactions with the subsequent content page to be gathered and transmitted over the computer network.