In a full-page ad in The New York Times on Nov. 9, 2004, the Mozilla project announced the release of Firefox 1.0, the first full version of the browser that has become the third most popular way to navigate the Internet, behind Google Chrome and Internet Exploder, er, Explorer. What makes Firefox unique is that it’s the only one of the three leading browsers that’s completely open source. Ten years later, more than 450 million people use Firefox, of which about 40 percent of the code is written by volunteers. In addition, its reach can be measured by the fact that more than half of its users employ non-English versions. The browser is available in 75 languages.