Official website of (one or more of the following):
The Mozilla Foundation
Mozilla Corporation
Mozilla Developer Network
Mozdev Community Organization
Good site/Useful, informative/Entertaining/Child friendly
http://www.mywot.com/en/forum/21694-mozilla-corporation-websites
Mozilla is the best browser and having excellent mail client formerly known as Thunderbird. However i give some less rating to this site in terms of child safety and privacy issues.
Mozilla Firefox, free web browser, is created by a global non-profit dedicated to putting individuals in control & shaping the future of the web for the public good.