links to news of a study comparing the currency and patch level of various Web browsers
"Firefox users were far and away the most likely to use the latest version, with an overwhelming 83.3 percent running an updated browser on any given day. However, despite Firefox's single click integrate auto-update functionality, 16.7 percent of Firefox users still continue to access the Web with an outdated version of the browser, researchers said. The study also revealed that the majority of Safari users (65.3) percent were likely to use the latest version of the browser between December 2007 and June 2008, after Safari version 3 became available. Meanwhile, Microsoft's Internet Explorer users ranked last in terms of safe browsing. Between January 2007 and June 2008, less than half of IE users — 47.6 percent — were running the most secure browser version during the same time period."