Mozilla was formed in 1998 by Netscape. Netscape was the first commercial company to take its intellectual property and open source it. They did it as a way to compete with Microsoft in the long run, who had many more people available to work on IE. By getting the open source community involved, it was hoped that this advantage could be lessened. The idea is that Netscape would be able to use some of the work from the open source community to put back into its products--a symbiotic relationship.
The code base of several million lines of code was hard for people to understand at first. Netscape was a company of 4,000 people at the time. The feedback from open source developers was that the code was too complex. It was decided that they would have to start again.
As the project became more successful, and distinct from Netscape, the Mozilla Foundation (sometimes known as MoFo) was formed in 2003 as a "not-for-profit corporation dedicated to the public benefit." The Mozilla Corporation was founded later in 2005 as a "wholly-owned subsidiary of the Foundation to coordinate the development and marketing of Mozilla technologies and products."
No one owns the Mozilla code. The Mozilla Corporation/Foundation do not own the code. They are simply the most active contributors, and custodians of various resources commonly used by the community (e.g., cvs, build machines, web sites). Much of the code in Mozilla and its products is written by developers outside the Corporation/Foundation. Some of these developers are employed at companies that ship products based on Mozilla, others are volunteers.
Various efforts have been made to quantify the size of the community involvement. In 2006 a study of bugzilla was conducted by Mozilla Corporation, showing the following:
Firefox
- 390 volunteer developers have written code
- 1,000+ extension developers (more than 2,000 extensions)
- 50,000 people have filed bugs
Gecko
- 1,300 volunteer developers have written code
- 20,000 people have filed bugs
Furthermore, it was found that 27% of all patches were checked-in by volunteers representing 24% of the changes made to the source.