Mozilla launches Firefox 4 browser

Mozilla has launched its highly anticipated Firefox 4 -- the latest version of its popular open-source Web browser sporting a new interface that aims to keep you focused on Web content.

As of 12:45 p.m. ET, it had been downloaded nearly 770,000 times.

You can create "App Tabs" for Web apps you use frequently and pin them to the browser -- say, for email, music or social networks. There is also a "panorama" view that lets you drag and drop tabs into groups. Mozilla says it can help you "save time while navigating many open tabs."

Mozilla is pushing a "do not track" feature that tells sites you visit that you want to "opt out" of tracking used for advertising purposes. (It's still up to the sites to comply.) Mozilla says the new Firefox is six times faster than the previous version.

Firefox 4 also embraces the latest Web technologies, such as HTML5, along with technologies that tackle graphics, video and sound capabilities.

This version of Firefox is competing head to head with the newly released Internet Explorer 9, Microsoft's newest Web browser, and with Google's Chrome, which was recently updated to version 10.

In a recent review, USA TODAY columnist Ed Baig notes that "Firefox 4 has a cleaner interface" but cautions that not all Firefox 4 changes are intuitive, including the panorama feature.