i think the google toolbar up.If you use that to search.Mozilla gets paid some part everytime someone searches then clicks on the ads.Not too sure.But i have a feeling that this is how it works
firefox's default search engine is google. Google pays them when people use it to search and click on ads, etc
or maybe they are some good people that power the OSS world I think they get funding from 3rd party sources
Maybe I'm wrong, but I cannot find anything in the HTML of the Firefox search homepage ( http://www.google.com/firefox ) or the URL of an actual search through that page which indicates an affiliate program through Google.
google pays through adsense on successful installs of firefox... see https://www.google.com/adsense/referrals although its a total rip off.
I sent Mozilla a $500 donation.... I dont think this is there main source of income but... You know they are affiliated so much with google.com so... And we all know google makes millions so
I think what we have to note is Google really wants people to use Firefox. It cuts at Microsoft and well we all know every attack from Google at Microsoft only helps them.
It's not using an affiliate link like regular Joes. Its probably a flat rate and could be server side or something.