If a site uses Google Analytics (using the new format that came out a year ago) and the user is logged in, the site will not appear for the user (only tested in FireFox).

A temp fix for now is to wrap the following code around your Google Analytics javascript:
<cfif application.security.isLoggedIn() is false>
...Google Analytics Javascript...
</cfif>

A quick Google search turned this up (not sure if it is related): http://blog.bvsoftware.com/post/2008/03/JQuery-123-conflicts-with-Google-Analytics.aspx