Mario, This is a reasonable presumption. I have another extension, ShootTheCookies, which used to be available for both Firefox and Chrome but that exists for neither at this point, but that continues to remain installed and functional in Firefox. I am sure if I were to delete it that there would be no chance of getting it back.
I am somewhat surprised that you didn't get some sort of warning on webvisum, but given that it requires login and you set it up to do that automatically that is probably what is keeping it active for you. I never did hear a peep back from the folks who created webvisum, and that definitely makes me presume that its days are numbered. But, if people are willing to make the config tweak that Bill White suggests, and someone keeps a copy of the XPI file that installs for Firefox, and the webvisum site and accounts still exist and can be create new ones its life can probably be "artificially extended." The work around due to its being unsigned is the first step in artificial life support. Brian
