Mozilla is out with the first beta release of the Firefox 4 browser, an important release given growing competition from Google Chrome. The new version of Firefox is based on the Gecko 2.0 web platform, and there is even a Feedback extension so that you can quickly fire your comments off to Mozilla. You can test extensions with the new version, but you need to install the Add-on Compatibility Reporter extension first in order to do so.

The new release of Firefox has much to offer. Here are some of the details on what's under the hood.

It used to be relatively easy for people to pick which browser to use, and one of the reasons that Microsoft's Internet Explorer still has dominant browser share is simpy that it came bundled with millions of copies of Windows on new computers. Firefox, more than any other browser of the last several years, made it a bit more complicated to decide on a browser. If you placed value on its extensions, which are hugely useful, it made more sense to use than Internet Explorer. Now, though, we're moving toward a browser landscape where you can't make a good decision on what to use without considering what you do online.

Microsoft is hard at work on its Internet Explorer 9 browser, following a period in which open source browsers such as Firefox and Chrome have steadily been eating IE's lunch. Judging from this blog post from Microsoft, there is some serious work going on under the hood of Internet Explorer 9 to make it competitive with other browsers and to reach out to new standards such as HTML 5. Can Internet Explorer seriously challenge the leading open source browsers at this point?