Firefox, the open source phoenix of a web browser that rose from the ashes of Netscape Navigator is now second only to Microsoft's Internet Explorer in adoption and leaves also-rans like Apple's Safari and Google's Chrome in the dust. Users love Firefox for its chameleon like ability to be customized to any use case through the by-now ubiquitous add-ons, and the rapid innovation (it was the first to introduce tabbed browsing) that is quickly copied by its rivals in a race to keep up.