There are many reasons for this, but the most important of them is with no doubt security.

There is much debate over the security of Web browsers, stemming mainly from Internet Explorer's vulnerability as a common target for hackers and virus writers. Microsoft regularly releases patches and updates to fix security holes in Internet Explorer that might allow someone to install malicious software or steal information from a computer. Firefox has not been the focus of hackers so far, but that doesn't mean it's inherently safer. For now, Firefox is enjoying a reprieve from viruses and hackers primarily because, compared to the widespread use of Internet Explorer, it is relatively obscure. Hackers haven't bothered exploiting Firefox yet, because the low yield means it wouldn't be worth their efforts. If Firefox ever achieves dominance among Web browsers, that can be expected to change.

About Mozilla Corporation

Formed on August 3, 2005, Mozilla Corporation oversees the development and distribution of Mozilla technologies and products, including the popular and award-winning Firefox Web browser and Thunderbird email client. Mozilla Corporation relies on the talents of a core group of employees, as well as a vast community of worldwide contributors, to build and deliver great, user-friendly products.

Mozilla Corporation is a wholly owned subsidiary of the Mozilla Foundation. Established in July, 2003, the Mozilla Foundation is a non-profit organization whose mission is to promote choice and innovation on the Internet. The Foundation provides organizational, legal, and financial support for the Mozilla open source software project, and governs the actions of Mozilla Corporation.