Web Monkey: The Firefox add-on website recently passed the two billion downloads mark.
That’s more add-ons downloaded than there are people on the web. Of course, that doesn’t mean everyone has add-ons installed — many of us have a dozen or more add-ons installed at any given time — but Mozilla has previously shown that some 150 million add-ons are in use every day.
Web browsers collect a massive amount of our web history data. These options can help with that.