Firefox 3.6 has recorded over 100 million downloads during the past 50 days, according to a new post  by Melissa Shapiro on Mozilla's official blog. Now, Mozilla wants Firefox loyalists still holding onto older versions of the browser to make the leap to the latest version. To this end, people running older versions will begin seeing a pop-up message to inform them about the latest version and urge them to update.

They will have to pick either one of the three options available to them: Ask Later, No Thanks, or Get the New Version. Mozilla also tried to address a widespread apprehension that already installed Firefox add-ons and Firefox 3.6 may prove to be incongruous. “It’s fast, stable, compatible with over 90% of the thousands of Firefox Add-ons, and contains new features such as lightweight themes and plugin version checking,” Shapiro wrote in a clear bid to allay such fears.

 Image Credit: Mozilla

Experimenting with new extensions is part of what makes Firefox great, but if you downloaded either the "Sothink Web Video Downloader", or "Master Filer", you probably snagged a nasty Trojan for your troubles. According to an entry on the Mozilla Blog both these extensions contain code which exploit vulnerabilities in all versions of Windows, and were downloaded close to 5,000 times before being spotted.

The extensions in question were contained in the "experimental" area of the official Firefox add-on site, and while it might seem like little consolation for anyone who got infected, users grabbing extensions from this section are warned before download that this could happen. Mozilla employs a special add-on scanner which supposedly checks all new entries for malicious code, but they were forced to acknowledge that the security process failed. "[Add-ons] performs a malware check on all add-ons uploaded to the site, and blocks add-ons that are detected as such," said yesterday's blog posting. "This scanning tool failed to detect the Trojan."

Mac and Linux users who downloaded these add-on's are unaffected, but anyone who used the extensions in Windows are being warned by Mozilla to delete all traces of the infected file, and run a virus scan. Mozilla is promising to boost the number of times it scans files for malware in the future, and will also step up how often it scans its entire catalog of add-on's.

Does this hurt your trust in Firefox extensions? Or was this bound to happen eventually?

Mozilla today unveiled the Jetpack Gallery, a place for developers to showcase their Jetpack add-ons.  Jetpack is a Mozilla Labs project that lets developers build Firefox add-ons using HTML, CSS, and JavaScript. While the newly launched gallery – still in beta - gives developers the opportunity to host and promote their Jetpacks, it lets Firefox users browse, install and rate Jetpacks. Installing Jetpacks is quite easy and doesn’t even require a browser restart, save for the very first Jetpack that a user installs. The Jetpack Gallery currently features over 30 add-ons.

I covered some awesome Firefox plugins a little bit ago, and it only seems fitting for Google Chrome to receive the same treatment.  But as you're undoubtedly aware, Google Chrome doesn't feature built-in extension support like other popular browsers on the market.  Or does it?

Actually, if you run the developer builds of Chrome, you can access the wonderful (beta) world of browser add-ons with but a few extra commands and tweaks.  Seeing as very few people who use Chrome know or care about this little modification, it stands that the actual world of add-ons for the browser is pretty small right now.  That said, there are still some neat extras that you can build into your browser--including some add-ons that mimic the best of what you'll find in Firefox's expansive database.

How to enable extensions in Google Chrome:

1. Download the Google Chrome Dev build
2. Right-click on the Google Chrome shortcut in your start menu, select properties.
3. Edit the target field so that it ends like this: \chrome.exe -enable-extensions 
4. Launch Google Chrome.  When you want to install an extension, drag-and-drop it into your browser.  To see a list of installed extensions (and to uninstall any you don't want anymore), type this into the browser address bar: chrome://extensions/

There we go!  Now, what extensions should you install?

ChromeGestures

What it does: This extension adds mouse-based gesture support to your browser.  What's that?  Well, instead of navigating your way around the Web using the browser's build-in buttons or keyboard commands,  you hold down the right-mouse button and draw specific patterns on your screen. Once your minor artistry is complete, the browser activates a command that corresponds to what you drew.  Simple, fun, efficient.

The caveat?  ChromeGestures is broken in the latest version of Google Chrome dev.  I include it on this list in hopes that when it's updated once again, you too will be able to enjoy all the mouse gesture-based fun that the Firefox folk get to have.

Download it here!

Aniweather

What it does: If you want to know the current and upcoming weather conditions for anywhere in the world, that's easy.  Getting this forecast to appear as part of your Google Chrome browser is a bit trickier.  Aniweather is a great add-on that displays the current and expected weather conditions in a status bar on your browser.  Hover your mouse over the little forecast and click, and you'll open up a Lightbox-style screen that shows you more detailed information and, should you request it, a ton of graphs and animations for what's going on around the entire world.  Neat!

Download it here!

Chrome Sticky Notes

What it does: Just to preface, this add-on is ugly as can be.  But for the functionality it offers, well, it's worth exploring.  In short, Chrome Sticky Notes adds a little button to your status bar.  Click it and a new, notebook-styled window pops up.  The text you enter here can be saved and reloaded as many times as you want.  Better still, if you stick URLs into your little sticky note area, a button at the bottom of the note will allow you to launch all the hyperlinks as separate tabs in Chrome.  It's not the prettiest way to make a sticky note, but it sure is convenient.

Download it here!

Gmail Checker

What it does: If there could be any clearer indication that Google Chrome isn't really coming to the table with a huge extension base just yet, this is it.  I surveyed a bunch of potential extensions to highlight in this article, but a scant few were interesting or stable enough to warrant a mention.  In this case, Google's own example of a Chrome extension--a simple little icon that tells you how many unread messages are in your Gmail inbox--is one of the most useful browser addons I was able to find.  

While developers will surely step up to the table once extension support reaches an official, stable build of Google Chrome, it's slim pickings for now, folks.

Download it here!

David Murphy (@ Acererak) is a technology journalist and former Maximum PC editor. He writes weekly columns about the wide world of open-source as well as weekly roundups of awesome, freebie software. Befriend him on Twitter, especially if you have an awesome app or game you're dying to recommend!