Mozilla Firefox 3 is focused on improved memory handling, performance, and stability, improved XUL, and new core components such as application data stored in SQLite. Mozilla Firefox 3 could break a few existing extensions and applications built on top of Firefox, and it will definitely include new optimizations if you like to build on the popular browser. Mozilla Firefox 3 should have additional JavaScript and SVG features if you're into that sort of thing.

Features in Firefox include:
- Easy migration: Switching to Firefox has never been easier now that Firefox imports data like Favorites, history, settings, cookies and passwords from Internet Explorer. Firefox can also import settings from Mozilla 1.x, Netscape and Opera.

- Smaller Download: Continuing efforts to make this the most efficient browser, the Windows version of Firefox is now only a 4.7 MB download, making downloading Firefox a breeze for dial-up and broadband users alike.

- New Default Theme: A new default theme provides a bright new look for Windows and Linux users.

- SmartUpdate: A new SmartUpdate feature notifies users of new versions of Firefox to ensure that the browser is always up to date.

- Help: A new online help system makes this one powerful, friendly browser.

- Extension/Theme Manager: New Extension and Theme Managers provide a convenient and secure way to manage and update the hundreds of add-ons that set Firefox apart from other browsers.

Mozilla Firefox also includes numerous bug fixes and incremental improvements, including faster page load speed.
- Popup Blocking: Stop annoying popup ads in their tracks with Firefox's built in popup blocker.

- Tabbed Browsing: View more than one web page in a single window with this time saving feature. Open links in the background so that they're ready for viewing when you're ready to read them.

- Smarter Search: Google Search is built right into the toolbar, and there are a plethora of other search tools including Keywords (type "dict " in the Location Bar), and FastFind (start typing the first few letters of some text in the page and Firefox takes you there).

- Privacy and Security: Built with your Security in mind, Firefox keeps your computer safe from malicious spyware by not loading harmful ActiveX controls. A comprehensive set of privacy tools keep your online activity your business.

- Hassle-Free Downloading: Files you download are automatically saved to your Desktop so they're easy to find. Fewer prompts mean files download quicker.

- Fits Like a Glove: Simple and intuitive, yet fully featured, Firefox has all the functions you're used to - Bookmarks, History, Full Screen, Text Zooming to make pages with small text easier to read, etc.

- S M L XL XXL XXXL: Firefox is the most customizable browser on the planet. Customize your toolbars to add additional buttons, install new Extensions that add new features, add new Themes to browse with style, and use the adaptive search system to allow you to search an infinite number of engines. Firefox is as big or small as you want.

- Setup's a Snap: At only 4.7MB (Windows), Firefox only takes minutes to download over a fast connection. The installer gets you set up quickly, and the new Easy Transition system imports all of your settings - Favorites, passwords and other data from Internet Explorer and other browsers - so you can start surfing right away.

- A Developer's Best Friend: Firefox comes with a standard set of developer tools including a powerful JavaScript and CSS error/warning console, and an optional Document Inspector that gives unheard of insight into how your pages work.