Do you use PortableApps' Firefox builds to test out Firefox betas or launch from a thumb drive? Firefox obsessive (and former Lifehacker intern) AsianAngel details the surefire way to bring your portable browser up to date.

Windows only: Reader David writes in about a user-contributed build of Firefox 3.5 Beta 4 using some custom patches and optimised build settings to make it run faster and use less memory.

Like its brethren browsers Google Chrome and Internet Explorer 8, Firefox is moving toward separating tabs into system processes, increasing browsing stability and taking advantage of increasingly common multi-processor systems.

There's a lot about the next iteration of the open-source Firefox browser to be geeked out about. From private browsing modes to tab preview panels, from punchier colours to really smart session restoring, there's been a lot of thought put into how people want to use the web. But perhaps the greatest promise in Firefox 3.1 is the one most users won't see at all—a serious overhaul of the browser's JavaScript engine, newly christened as TraceMonkey. If you don't obsessively follow the Mozilla developer's blogs or read insider tech news, you might have a few questions about TraceMonkey—like, say, what's different about it, how much faster is it, why that matters, and how you can try it out right now. We've compiled a primer on TraceMonkey's features and uses, as well as how to experience it. Read on to see what's new under the hood in the upcoming Firefox. Graph via Brendan's Roadmap Updates.

Owners of MacBooks with multi-touch trackpads can try out an experimental Firefox 3.1 build that supports finger gestures—swiping left and right for back and forward, pinch zooming, and twisting between tabs, amongst others. The gestures may or may not make it into the final 3.1 release, but at least one developer finds the tab-switching twist a big convenience.

Three days after Tuesday's release of version 3.0.2, Mozilla pushes out Firefox 3.0.3, an update that fixes one bug: "where users were unable to retrieve saved passwords or save new passwords." Hit "Check for Updates" from the Help menu of your copy of Firefox 3 to get this latest version.

Your copy of Firefox 3 will give you the old "update available" notification soon—or you can hit the Help menu and choose "Check for Updates" instead—to get version 3.0.2, which gives you a slew of security updates and bug fixes related to keyboard shortcuts (on Mac) and web page layout.

The Mozilla Links blog reports that Firefox's next release, version 3.1, will ship with colour profile support turned on by default. Colour profile support shows richer colours in certain images in your browser; if you can't wait for 3.1 to drop, here's how to enable it in your copy of Firefox 3 now.

The Tools for Thought blog runs down 15 useful commands you might not have known for Ubiquity, the experimental Firefox extension that acts on your typed requests (which Gina showed us around last week). Among the cooler uses are highlight, which leaves behind a semi-permanent yellow on selected text, and check Friday, which relays your Google Calendar appointments. Ubiquity testers, what commands are using to get things done? Offer up the code in the comments.

Firefox 3 comes with several preferences baked into its options dialogs, but there are still a few you can only access by rolling up your sleeves and digging into its configuration manually. Power users have been diving under Firefox's hood to get their browser to behave just how they like since version 0.9, but Firefox 3 offers some new settings that customise its new features. Let's take a look at our favourite Firefox 3 about:config tweaks for customising your browser.

Blogger Marios Tziortzis details how to set up previously mentioned Mozilla Weave—Mozilla's Firefox-syncing tool—on your personal web server. Setting up Weave with your own server means you don't have to rely on Mozilla's servers, and you can keep your private data, which includes passwords, bookmarks, cookies, and browsing history, on your own web space. It's not a terribly difficult process, so if rolling your own Mozilla Weave server appeals to you, it's worth a go. Setting up Mozilla Weave on your Server

Firefox 3 doesn't store your bookmarks in the plain old HTML file that Firefox 2 did, so desktop launchers like Quicksilver and Launchy can't index them properly. But the HackCollege blog has a solution: a Firefox 3 about:config tweak that makes Firefox automatically export your bookmarks to a file. Change the browser.bookmarks.autoExportHTML value from false to true to get a bookmarks.html file saved to your Firefox profile directory each time you shut down your browser.

In Firefox's Help menu choose Check for Updates to download Firefox 3.0.1, a minor update that fixes Firefox 3's most common causes of crashes. This update won't shouldn't cause any add-on incompatibilities (but apparently does here and there according to commenters).

All platforms with Firefox: Even though Firefox 3 has decent file and FTP browsing built-in, the Firefly extension aims to turn the 'fox into a robust file manager. Browse your local drives and folders in Firefox using Firefly, which offers tabs, can split your screen to view several folders, preview images, open, rename, copy, and delete files, and display a hierarchical folder tree in the sidebar. Not sure Firefly is quite as polished as it could be, but if you're dying for a Windows Explorer alternative and Xplorer 2 and others like it aren't cutting it, Firefly is an option. See this Firefly tutorial for more of what it can do. Firefly is a free download which works (almost) wherever Firefox does—the developer says definitely Windows and Linux, but less testing's been done on the Mac.

Firefly

When you want to backtrack a few paces in your web surfing clicktrail but not lose the page you're on, in Firefox 3, click on your current tab, hold down the Ctrl key and drag it. This will duplicate the tab and keep its history in the copy—that way you can back out and stay where you are in another tab. Sadly this trick only works in Firefox for Windows, not on the Mac. Don't forget, you can also drag tabs between browser windows in Firefox, too. What's your favourite Firefox 3 shortcut? Let us know in the comments. Firefox 3 features you may not know

From the files of the Maybe New To You Dept.: While Firefox 3 should be a bit less crash-prone than its predecessor, it isn't bulletproof. Type about:crashes into Firefox's address bar, and you can see a list of your browser crashes, when they happened, and click on them to get details of what happened. Some of the reasons and reports might not be in plain English, but a little copy/paste-to-Google could help diagnose your problems. This will only list the crashes after which you clicked "Submit" on the resulting pop-up, so you might want to think twice before hitting "cancel" after your next sudden failure. about:crashes - An Answer To Why Firefox Crashed

Mozilla officially announced today that Firefox 3 set the Guinness World Record for most software downloads in 24 hours, totaling at an impressive 8,002,530 downloads. Now that it's official, don't forget to get your personalised Download Day certificate.

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The newest version of Mozilla's experimental browser-syncing tool, Weave, just hit the net, and it's seen a few marked improvements since it was first available. Going beyond bookmarks, Weave can match up your Firefox 3 settings, cookies, browsing history, and even tabs between browsers, with experimental support for passwords and form data—in other words, just about everything except extensions, themes, and plug-ins. There's a lot more to come, and it's still a pretty rough around the edges—this is, after all, just version 0.2—but follow along after the jump to see some of what Weave can do, or at least one day will do, to keep your Firefox browsing consistent and convenient.

Web utility del.icio.us to Firefox merges your bookmarks from social bookmarking web site del.icio.us—tags and all—with your existing Firefox 3 bookmarks. Why might you want to do this? Because the new and improved bookmarking functionality in Firefox 3 supports tagging, but since previous versions of Firefox did not, you've already got tons of bookmarks with no tags.