Firefox 4 Beta includes Firefox Sync, which promotes common browsing on desktop, notebook and mobile platforms. With Firefox Sync, users can take your browsing history, bookmarks, tabs, passwords and form-fill data with them anywhere so they never have to retype passwords or long URLs again.

 

In addition, Firefox 4 for mobile also incorporates pinch to zoom. 

 

“A major focus of this release is to increase performance and responsiveness. Two of the big architecture changes are Electrolysis and Layers. Our alpha contained Electrolysis which allowed the browser interface to run in a separate process from the one rendering Web content, resulting in a much more responsive browser. This beta brings the Layers pieces which improve overall performance and in graphics areas such as scrolling, zooming and animations” said a post on the official Firefox blog. 

 

“Firefox 4 Beta for mobile is significant step forward in sharing a personalized, seamless and encrypted Web experience across devices. Developers have the power to use the latest Web technologies like HTML5, CSS and JavaScript to to build fast, powerful and beautiful mobile apps and add-ons that can reach millions of devices. We are excited to see the innovative and valuable mobile add-ons that developers will build for Firefox.”