16. The non-transitory machine-readable storage medium of claim 15 , wherein the operations further comprise redirecting the subsequent request from the first document to the second document.
15. A non-transitory machine-readable storage medium comprising instructions that, when executed by one or more processors of a machine, cause the machine to perform operations comprising: detecting a request for provision of a first document that is available for provision; updating a count of referrals based on determining the request was sent from a set of one or more networks, the count of referrals comprising a number of requests for provision of the first document; retrieving a second document based on the first document and on the count of referrals transgressing a threshold value; and providing the second document in response to a subsequent request for the first document, the subsequent request occurring after expiration of an availability of the first document.