In less than 100 days after the release of the open-source browser, Firefox downloads exceeded 25 million. Firefox now holds 4.8% of the browser market, compared to Microsoft Internet Explorer's 92.7%.

Much of Mozilla's success is founded on the woes of IE. However, there is much more to the browser space than security problems and market share. Browsers can be thought about in multiple ways including: security, features and development

Security
With the mutation of viruses, anti-virus software has a difficult time keeping clients updated. A few years ago, on a sunny afternoon, a major IT company in Birmingham sent hundreds of people home due to a virus infiltration of its network. Someone had clicked on an email from "Administrator" asking the person to following the instructions posted in the attachment. You can imagine what happened next. [And yes, the person that opened the email was a manager.]

Even with all the safeguards in place, viruses cause havoc. Every major company in the U.S. has problems with viruses. Since IE security settings actually impact security of other applications like Outlook, I have a tendency to run IE with the highest security settings, and active scripting turned off. The active disabling also disables much of the websites that one visits, this is partly due to the fact that Microsoft has JavaScript/ActiveX scripting in the same setting.

I wrote some technical articles some time ago, and participated on message boards. Now I receive over a thousand emails a day. However, I have no anti-virus software installed on any of my machines. With Active Scripting turned off, it is not required. Insecure software like IE is the problem, not viruses. [To make an analogy, we will never get rid of germs and diseases, but we can make our environments safe from germs and disease.]

Features
From an usability standpoint, there about 101 things Mozilla browser can do that IE cannot. However, there are products like Avant that basically upgrade IE to have features like FireFox. I've heard rumors that Microsoft is coming out with IE 7.0 by the end of the year.

However, I don't know how it compares to all the stuff going on at mozdev.org. The projects hosted on mozdev create applications and add-ons that are based on Mozilla. Which leads into the next topic.

Development
FireFox is just the tip of the iceberg. Mozilla (like Eclipse) is based on the 'Microkernal' design pattern. Microkernal separates a minimal functional core from extended functionality. The pattern applies to software systems that must be able to adapt to changing system requirements.

Microkernal is hugely different than the IE component based structure. This difference allows development on the Mozilla browser to happen at a significantly quicker pace. Productivity is demonstrated in the fact that other browsers in the market are having a difficult time keeping up with Mozilla projects. Furthermore, IBM is putting resources into Mozilla as recognized in the x-forms project.

Mozilla is starting to have that feel of future dominance that Eclipse had several years ago. Mozilla is a significantly better-architected application, and like other well-orchestrated open-source projects, Mozilla contains the quality characteristic.

Bottom line, Mozilla will be a major player for sometime. Now, if Mozilla were just written in Java...