A year ago, Mozilla entered the Guinness Book with a little over 8 M Firefox 3 downloads in 24 hours. Today, still in the first day, Firefox 3.5 has an average of about 50 downloads /sec and a total of 3.6 million downloads at July 01 10:30 AM GMT. It won’t probably break its own record, but 3.5 is a worthy update considering the large number of improvements over 3.0 like native video. No need for Flash/Silverlight anymore.
Native Video. Support for the HTML 5 tags <video> and <audio> with native support for open source Ogg Theora encoded video and Vorbis encoded audio, both developed by the Xiph.org Foundation. The result? One does not need Flash nor Silverlight to play video/audio anymore. A Theora video is considered part of the page as any other HTML component. When the user zooms in/out, the video is also resized along with the text.
Script engine. A new and faster JavaScript engine. Called TraceMonkey, some benchmarks reports talk about being 20 to 30 times faster than SpiderMonkey, the script engine used by Firefox 3. But that depends heavily on the test suite used. In many tests, TraceMonkey is twice as fast as SpiderMonkey and almost as fast as Chrome 2 and Safari.
Geo-location. When visiting a location aware web site, Firefox uses the IP address and the wireless connection points used to determine the location of the user. This is done by sending the IP information to the default geo-location service, Google Location Services, which in turn returns an approximation of the user location. The location can be used by the web site to provide information pertaining to the user, like the restaurants existing in his area. This feature can be disabled to protect privacy.
Privacy. In privacy mode the browser does not keep track of any browsing activity: history, cookies, downloads, web forms, search.
JSON and Web Worker Threads. Firefox 3.5 has native JSON parsing making it much safer to handle JSON code execution. It also supports HTML 5 worker threads allowing to pass script code execution to background threads. The result is that a script will not block the page while the code is executed.
Color Profiles. Firefox 3.5 uses a dynamic color profile scheme to see pictures as the author intended.
Other. Support for: downloadable fonts, CSS media queries, JavaScript query selectors, HTML5 local storage and offline application storage, "canvas" text, ICC profiles, and SVG transforms.
Firefox 3.5 is available for download in more than 70 languages for Windows, Mac OS X and Linux.
Useful links: Firefox 3.5 Download Page, Features for Developers.