Rated 5 out of 5 stars
Like another reviewer here, I'm not wild about site search results and have it turned off, as I do AVG's LinkScanner Search-Shield. And I dumped Web Of idioTs long ago.
That said, this is The Next Big Thing in security extensions for Firefox. I've been using TrafficLight since June and watched it get better and better to its current excellence. It's so effective I've unchecked Firefox's two "Block reported..." Security settings.
It should be noted that this extension and the ones for Chrome and Safari in Windows, Linux and Mac OS X are not the same as the the "full" version. For Windows only, it's downloaded as WebInstaller.exe from the BitDefender site and it installs full-time scanning engines.
The extensions rely on the cloud except for antiphishing and whitelists which are signatures stored locally and updated regularly, checked for hourly. You can find the sigs in prefs.js in Firefox and in a Chrome .localstorage file.
I'm looking forward to TrafficLight's development and evolution. What amazes me the most, tho, is this is from one of the industry's most stellar developers and it's... Free!