13. The system of claim 11 , wherein the second network-based document is unique to the identifier of the user, wherein the network address is a URL of the second network-based document, and wherein the identifier of the second network-based document further comprises information about the identifier of the user.
13. The system of claim 11 , wherein the second network-based document is unique to the identifier of the user, wherein the network address is a URL of the second network-based document, and wherein the identifier of the second network-based document further comprises information about the identifier of the user. 14. The system of claim 13 , wherein the information about the identifier of the user comprises a hash of the identifier of the user, and wherein the hash is appended to the URL.