Firefox 3 promised to improve security for the users but it came at the cost of usability. The unpopular Add Exception prompt is driving me and many other users nuts when we have to add an exception for genuine sites like google.com, godaddy.com and yahoo.com I was trying hard to find some hidden option to disable this prompt completely. But Firefox developers have put not even a hidden setting to remove this prompt completely.
My Hack is not complete solution to this problem but still makes it easier to add exceptions and browse the sites easily.
Type about:config in your firefox’s address bar and
set browser.ssl_override_behavior = 2
set browser.xul.error_pages.expert_bad_cert = true
Now this won’t remove that prompt completely but atleast you won’t have to retrieve certificate manually as it will be prefetched now.