Mozilla has released Firefox 4 Beta 4, bringing two very interesting features to the table: Panorama (previously called Tab Candy) and Sync.

Panorama is a nifty visual tool that lets you overview all of your open tabs and group them into sets with a simple drag-and-drop interface. It's activated via an icon at the right end of the bookmark bar, which takes you to your tab playground, where you can expand or delete your tab sets, create new ones and organize them around the canvas as you see fit.

I don't see the need to organize my tabs in a way other than the default, but then again, I'm not an extreme tab user — I've seen people with 30+ tabs open at all times, and in such cases a feature like Panorama can come in handy.

Another interesting update in the latest beta of Firefox 4 is the inclusion of Sync, a feature that lets you synchronize your bookmarks, history, Awesome Bar, passwords, form-fill data and open tabs across multiple computers and your iPhone if you use Firefox Home. As far as security and privacy go, Sync doesn't track your history, and encrypts all of your data before sending it to the server.

For many users, Sync is not only a wanted feature — it's a must-have. Right now, a Firefox add-on called Xmarks delivers most of the functionality of Sync, and even brings some extra features, such as search enhancement and web discovery. But Firefox is playing catch-up here, as Google's Chrome and Opera already have a similar feature, so it was definitely time to include something similar in the default version of the browser.

Firefox 4 Beta 4 is available for Mac, Linux and Windows users here.