Since Linux Mint 12 this is not the case anymore. They listened to their users, and removed the Google Custom Search.
As a convenience to its users, Linux Mint has a dedicated webpage where you can easily add search easily with one click: http://www.linuxmint.com/searchengines.php You can of course add search engines in any other Firefox supported way also.
As a convenience to its users, Linux Mint has a dedicated webpage where you can easily add search easily with one click: http://www.linuxmint.com/searchengines.php You can of course add search engines in any other Firefox supported way also.