Mozilla’s Firefox web browser is now on 28% of computers in Europe, according to a study by French companyXiTi Monitor. That figure is up from 24% back in March and just 21% a year ago. A separate study by W3Counter gives Firefox a 24% market share. One thing for certain, though, is that the increase has come at the expense of Internet Explorer. Its share, both studies agree, is at just over 66%, down from 73% last year. In the U.S. Firefox hasaround 19% of the market. According to the XiTi Monitor survey, Opera, Safari and Netscape followed IE and Firefox in popularity, with 3.5%, 1.7% and 0.3% respectively. Firefox is most popular in Slovenia, Finland, Slovakia, Hungary andPoland, where it enjoys market shares of well over 35%. Its biggest gain has been in Ireland where its share has risen 14% since March, to 38.6%. It’s a huge boost for Mozilla, as thecompany’s European president, Tristan Nitot, acknowledged. “Four years ago, many of us were laid off by AOL Time Warner, which no longerbelieved in the Mozilla project. Firefox wasn’t even launched yet, and we didn’t have a business model. It was a dark moment for the Mozilla project.” But now there’s definitelylight at the end of the tunnel, especially as Mozilla hasn’t undertaken any special marketing in Europe. Instead, Firefox’s reputation seems to have aided its growth, along with someEuropean anti-Microsoft sentiment.