The MozMarks Firefox extension has been discontinued, due to a lack of time and the availability of alternatives (such as del.icio.us). The old MozMarks site can still be found here.
I also developed a Firefox extension for the Gubed PGP Debugger. It is available on the Gubed Homepage (Click on "Download"). Currently (15/01/2006), the 'official' version only supports Firefox 1.0. If you want the latest version (v0.15), which supports Firefox 1.5, click here.