Shortly after releasing version 16.0 of the Firefox Web browser, Mozilla replaced it with Firefox 16.0.1, which addresses a security vulnerability that could allow a malicious site to determine which Web sites you had visited, and access their URLs or URL parameters. Regardless of the version number, Firefox 16 is a minor release. Most notably for Mac users, it now offers preliminary VoiceOver support, though Josh de Lioncourt of Mac-cessibility says that performance is poor. Mozilla also says that Firefox 16 offers initial support for Web apps, defined as apps built using standard Web technologies that are installed by a user, are self-contained, don’t always require the trimmings of a Web browser, and can be built to run offline. Mozilla is working on the Mozilla Marketplace to host these Web apps, much as the Chrome Web Store hosts Web apps built for Google Chrome. Other changes in Firefox 16 include a new developer toolbar, an error count for the Web Console, and a new command line for quick keyboard access for developers, plus a few bug fixes. Still unresolved for some users is a bug that can cause slow scrolling in the main Gmail window. (Free, 33.3 MB, release notes)