Twice as fast as Firefox 3
The average user will not find the previous version slow, and so may not notice version 3.5 working much harder. But it is, and pages are loading closer to the speed of Chrome now.
But fast rendering does not a good browser make. Not alone, anyway. So on top of it is a Firefox interface largely identical to the last, at least aesthetically. And that means no 'Start private browsing' button is displayed, which is perhaps a small oversight. To enable this questionably inconspicuous feature, hit up Tools, then Start Private Browsing.
Private browsing mode
Private browsing won't store your browsing history, passwords entered, cookies and items in the browser's cache (such as temporary images, for example), or a log of what you've downloaded. This is a feature Firefox is late to the game on, as Internet Explorer 8, Google Chrome and Safari users have enjoyed this perk for a while.
It's hard to get excited about such a feature unless you're the type of person who involves tin foil, hats, and anything that combines the two, but it works as advertised. Funnily, it doesn't mind pulling in passwords and autocomplete data already saved by Firefox.
Firefox knows where you are...
Perhaps the most interesting new feature is location-aware browsing. This is a feature that lets Firefox detect your position on the planet, then pass that location to whatever Web site you're on. It sounds like a privacy nightmare, right? Except it's not. Not really, anyway. You have to grant permission to every site, should one ask for it, and your location is discovered either based on your IP address or the geographical location of the Wi-Fi hotspots in your vicinity. Firefox works with Google's Location Service to do this, as it knows where on a map these hotspots are.
And in our tests it not only pinpointed our town, but even our street. The most obvious use for a feature like this would be within a Web site for a chain of coffee shops, say Starbucks. If you visit the Starbucks site to find where the nearest store is, it can use Firefox to determine your location to within a couple of hundred metres or so, and figure out which cafe is closest.
It works best with Wi-Fi enabled. When using our IP address -- which could position us practically anywhere in the country -- Firefox only knew we were somewhere in London. While that's useful if you often find yourself in countries you didn't know you were visiting, it's not going to narrow down where the nearest Venti black Americano can be snagged from.
Acid3 and the compliance to standards
Other new features include a score of 93/100 on the industry standard Acid3 test, which tests a browser for compliance with Web design standards, support for advanced HTML5 elements that you can expect to be used much more over the next few years, along with a number of additions to make Web pages with rich layouts and content render better.
It's an impressive browser with genuine innovation behind it. The only reason not to upgrade from Firefox 3 immediately is if you myriad extensions aren't compatible, and many of ours weren't. But otherwise, it's getting a hearty thumbs up. Download it here.