For instance I was looking at the request from a asp.net application and it passes a view state form variable when the form is submitted that looks like this:
__VIEWSTATE:/wEPDwUJMzc4ODIxMTU4D2QWAgIBD2QWCgICDxYCHgRUZXh0BQVlbi1VU2QCBA9kFgICAQ8WAh4JaW5uZXJodG1sBTlDV0RTIC0gQ2VydGlmaWVkIFRBQS9XSUEgVHJhaW5pbmcgUHJvZ3JhbXMvUHJvdmlkZXJzIExpc3RkAg4PFgIeBXN0eWxlBSRWSVNJQklMSVRZOmhpZGRlbjtwb3NpdGlvbjphYnNvbHV0ZTtkAhAPDxYCHgtOYXZpZ2F0ZVVybGVkZAISD2QWDAIBD2QWAgIBD2QWIAIBDw8WAh8DBSh