>>user_pref("network.http.sendRefererHeader", 0);
>
> Hmm. I'd prefer not a simple on/off switch, but that plus the ability to
> enable the Referer header for requests for anything from the same site or
> which is part of the page which is being fetched (regardless of whether the
> request was generated directly by the user or as part of the page fetch).
Um, that's how it works. If I go to www.mozillazine.org and check the
referrer, it's blank. If I then follow a link to another page on
mozillazine the referrer is http://www.mozillazine.org/
Check it yourself in the page info (Trunk build).