1. A computer-implemented URL rescue process, said URL rescue process comprising: by a server system that hosts a site: receiving a Uniform Resource Locator (URL) request from a user device, said URL request specifying a URL that includes a domain name and a character string; detecting that the URL is invalid; and in response to detecting that the URL is invalid, executing a set of one or more URL rescue strategies to attempt to locate site content that is related to the invalid URL, said set of one or more URL rescue strategies including a search term mining based strategy that comprises: extracting, from the character string of the invalid URL, a set of one or more search terms for executing a search of content of the site, wherein extracting the set of one or more search terms comprises identifying at least one substring of the character string, and comparing the substring to entries in a selection list; executing a search of the site content using the set of one or more search terms, wherein the search is executed using an index of site content; and sending results of the search to the user device in response to the URL request.