Bruce Perens gave a talk where I work today on the topic of Open Source in the business place. One of the topics that came up was Firefox, where he mentioned that the next version of Internet Explorer and that they took that from Firefox. (Some might disagree about where they stole it from...)

Anyway, I got to thinking. As hinted above, tabbed browsing really wasn't an open source innovation. But what really is has to be Firefox's extension mechanism.

I have a love-hate relationship with XUL. There are some things I'd do differently, but ultimately, the ability to add cross-platform features to the browser UI via XUL overlays is an extremely powerful ability.

Everyone has their favorite browser extensions. Some people make like a certain feature that an extension adds that others would rather not have. Extensions allow them to have the feature they want while leaving them out of other's browsers.

I happen to like mouse gestures, so I use the Mouse Gesture extensions. I also like the Forecastfox extension, which allows me to see upcoming weather reports in the browser status bar.

Tab browsing is nice, but the extension ability is easily the best innovation I've seen in any browser.