Sites are insulated from the effects of browser upgrades and patches because the authentication and authorisation are standards compliant and the results are not dependent on browser interaction ...

The isapi authentication filter includes a feature that greatly simplifies tracking an authenticated user through multiple pages of a web site.

On every request for a file in the protected area a custom header is inserted into the request. The request is accessible from dynamic pages as the cgi variable 'HTTP_USER'. This eliminates the usual need for developers to track users via url variables, hidden forms variables or cookies ...