Ghostzilla was an open source web browser for Microsoft Windows based on the Gecko HTML renderer used by Mozilla.
It runs the browser inside the window space of another application e.g. in Microsoft Outlook, where the page was
then made to look like the content one would expect in an email, leaving any passers-by with the impression the person was reading e-mail.

From May 2004 until January 2005, the project was removed from the website, due to a copyright claim from Mozilla.
It later returned with open source code, but with warnings about the potential for misuse.
As of February 2007, the site has been suspended and is no longer available.

* The Ghostzilla window disappears when the mouse cursor is moved away from it, allowing the user to very easily hide it.
* The user can set the preferences to set security (hiding) levels. For example: He can display no images unless hovered
over by the mouse (they stand out, thus making it more easily recognized as the Web), or display plain grey text on a white background.

Screenshot on top of outlook
Screenshot before
Screenshot after
Screenshot bare is gone, visit the archive.
Last ever archived version of Ghostzilla site.

Author is unknown, but src code was released via GPL, so a copy was moved to sourceforge.