respawn_redux [presistent cookies based on If-Modified or Etag headers]

http://ashkansoltani.org/docs/respawn_redux.html

An article that describes a method to create a permanent cookie based on If-Modified and Etag HTTP headers. Currently this is used in “the wild” by several banner and add networks. The method is possible because of the simplified implementation of If-Modified implementation in all modern browsers (browsers do not validate values of if-Modified as DATE)