7. The method of claim 6 , further comprising redirecting the user computing device to the second URL.
6. A computer-implemented method for rescuing invalid URLs included in URL request messages from user computing devices, the method comprising: by a computing system that comprises one or more computing devices: receiving a URL request from a user computing device, the URL request comprising a URL that includes a name of a domain of a website and a character string, the character string including a first product identifier that corresponds uniquely to a first product; determining that the character string references an invalid location on the website; obtaining the first product identifier from the character string; obtaining supplemental product information for the first product using at least the first product identifier; identifying a second product based at least partly on the supplemental product information for the first product, wherein the second product is different from, and supersedes, the first product; and responding to the URL request by providing a second URL corresponding to a page having content associated with the second product, said second URL including an identifier of the second product.