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: determining whether the character string of the invalid URL includes at least one term that is suitable for use as a search term for executing a search of content of the site, said determining comprising identifying at least one substring of the character string, and comparing the substring to entries in a selection list, the selection list including at least one of the following: a whitelist, a blacklist, a list of parameters; when the determination results in identification of a set of one or more search terms, executing a search of the site content using the set of one or more search terms, and sending a result of the search to the user device in response to the URL request, wherein the search is executed using an index of the site content.