See a longer explanation.
BTW: It is pronounced "Beo-necs".
As I write this, there is no open-source distribution of Mozilla for end-users, apart from some packages in Linux distributions.
We were unhappy with the way people were tracked by the major browser vendors while they surfed the web, and we didn't like to see the masses being trapped in a partner-websites world or forced to use a certain browser, operating system, registration system or whatever. We believe in open competition on a distributed Internet.
We also disagreed with some of the feature vs. security trade-offs other browser vendors made.
OTOH, Netscape recieved the source code of many individual volunteers (including many of the Beonex people) and companies who/which contributed to the Mozilla project. See also our policy about open source.
It's a give and take.