If all goes to plan, Mozilla will be releasing its much anticipated Firefox 3.5 browser any day now, and certainly by the end of the month. It's been a long wait for the Firefox faithful, who first got a glimpse of the oft-delayed browser in Alpha form back in July of 2008. More recently, Mozilla has rolled out a pair of Release Candidates, giving fans (and critics) a pretty good idea of what to expect when the final version goes Gold.

The most ambitious update to Firefox yet, version 3.5 delivers a ton of coding improvements and a handful additional features Mozilla hopes will help close the market share gap with Microsoft's Internet Explorer. Join us as we take an in-depth look at what's new and highlight which features have us most excited about Firefox 3.5!

Private Browsing Mode

Right out of the gate, probably the most anticipated new functionality of Firefox 3.5 is the Private Browsing mode, less affectionately (or more affectionately, depending on your perspective) known as Porn Mode. Firefox joins a growing list of browsers to add a private browsing option, whereby all traces of your surfing history are eradicated once you close the browser or exit the private session.

In Firefox, selecting Start Private Browsing from the Tools menu (or pressing CTRL+Shift+P) closes all open browser windows and opens up a discrete window. You can then log into your Katie Morgan fan club account or, perhaps more wisely, browse gift ideas for your significant other while keeping it on the down-low. Once you exit Private Browsing mode, all your tracks will be erased, and whatever browser windows you previously had open will be restored, tabs and all, albeit each one will have to be reloaded. And unlike Google Chrome, you can't have both a Private and non-Private browser window open at the same time.

If you forget to enter Private Browsing mode or load up a website you later wish you hadn't, Mozilla has added a couple of different ways of how you can approach this. One way is to delete your browsing history for just the past hour or past several hours.

The other way is to go into your History, right-click the site you want to erase from memory, and select 'Forget about this site.' Rather than scour through the contents of your History, Firefox nukes all instances of the selected site, a particularly handy feature when gift shopping.

Websites Get Identified

Have a suspicious feeling about the site you're about to order from? Websites now come with an identity overview giving you quick access to a site's security certificate. Clicking the More Information button brings up even more details, such as how many times you've visited the site in the past, what cookies are being stored, and what passwords are being saved.

Retrieve Recently Closed Tabs and Windows

Clutter up your desktop with too many windows and you may find yourself haphazardly closing everything in sight, including that browser window you didn't mean to exit out of. Oops! But like an undo button, Firefox 3.5 adds the ability to reopen Recently Closed Windows via the History button, right underneath the Recently Closed Tabs section. 

Video Support is Augmented

Firefox 3.5 handles video much better than any previous release, particularly with support for Open Video. In addition to the HTML 5 video tag, Firefox 3.5 ships with the Ogg Theora codec. This means that without a plugin, you can watch any video that is encoded using Ogg Theora. Theora files can be embedded directly into web pages, giving viewers all the standard controls they're used to, like volume adjustment, pause, etc. In addition, depending on the video source, you can right-click and save the video clip to your hard drive.

Even cooler is how Firefox lets you interact with videos built around the open standards. Dubbed Dynamic Content Injection, other images and videos can be inserted into specific points of a video in a sort of augmented reality fashion. Technically, the same types of tricks can be done in Flash, but it's a lot more complex and typically requires the entire page be coded in Flash.