As usual, though, the changes that are closest to my heart are the ones that affect your immediate interaction with the browser - what it looks like and how it behaves. In addition to important foundational improvements like more responsive pinch-zooming and clearer text rendering, there are number of things that I'd like to point out in particular.
Revised Android-inspired theme
The "theme," or look, of Firefox on mobile has undergone an overhaul. We've tried to make something that feels appropriate on Android, borrowing, for example, from the platform's flat square toolbar button look, its bubble popups, and context menus styles, while still maintaining a connection to Firefox for desktop platforms. We're still fine-tuning, but it already feels, to me, much cleaner and clearer than our last version.
In many ways, a browser's most important job other than rendering the web is to help you find your place in it. The web is huge and, without some help, finding the sites that matter to you can be very difficult. This is the rationale behind Firefox's awesomebar (or awesomescreen, in mobile) — it helps you make sense of your parts of the web without requiring you to do a lot of filing, configuration, or management. You wear it in just by using the browser; it gives you quicker and quicker access to the sites you visit often and have visited recently, while also minimizing the amount of typing you have to do.
On mobile devices, we decided to concentrate all the ways you find your sites into one place. The awesomebar's algorithm curates a default "all pages" list based on what you tend to do, but you can also get right into your organized bookmarks if you know exactly where you're looking. If you want to find a site you've seen recently, and that's all you remember about it, your history is right at hand. And, finally, you can see the sites that you already have open on your desktop computer, via sync, right here as well.
When you type, the awesomescreen pulls up your best matches from across all the categories, as usual. Bookmarks and sites on your desktop machine are marked with icons to give you some context — for example, if you type "wombat" and many results come up, you can quickly recognize the one you're looking for because you can see that it's the one you just had open before leaving your desk.
To make room for more awesome results, especially when a virtual keyboard is present, we've moved the multiple search engines available in Firefox to a search button, next to the field. You can access all of the built-in search engines, as well as any you add from the web, here.
Undo close tab
The ability to reopen an accidentally closed tab is as useful while mobile as it is on the desktop, where this feature is very popular. We've found an elegant way to surface this feature here: until you navigate away from the tab sidebar, the most recently closed tab will appear, reopenable, at the bottom of the area. One tap brings it back.
Taking something that you've found or created on the internet and showing it to others is now a basic act of web-use. In Firefox 4 for mobile, and now more fleshed out in beta 2, you can share links and images from almost wherever you find them, and do so through the Android sharing system.
You can long-tap links or images in webpages to share them, as shown above. You can also select "Share Page" from the site menu to share the page you're currently on. Finally, you can share by long-tapping on any item in the awesomescreen, regardless of whether it's a bookmark, history item, or page from your desktop machine.
Please share your feedback with the team as you use beta 2! There's a simple mechanism for doing so in the included Beta Tester Tools panel. We're eager to hear what you think!