Mozilla can be more ambitious. Or atleast as bold as they once were, when they took on Microsoft.
If they can convince Baidu, Yahoo et al to keep them open, independent and competitive against the likes of Apple, Google or Microsoft, then there is no reason they can't pull the same thing off to fund an open social network or a open search engine that can shake things up a little at Google and Facebook.
I am really quite sick of the Google and Facebook ivory towers deciding where and how things should work. Most of these decisions are based on empire defense rather than the common good.
They speak the language of the common good, but constantly do things that benefit them disproportionately.
So what is their purpose at the end of the day, other than "... we are the rich; we own america. God knows how. but we intend to keep it".
They need saving from themselves. And I am glad Mozilla exists like a Ralph Nader does to keep things honest.