Yes, I agree with your addendum. This is what we have done with Akvo.org. Nearly 3 billion people do not have clean water to drink or adequate sanitation. That is what I call a large market and a big problem. We have taken the open source approach to try to address this from an internet service point of view. Even though we haven't released any code yet, we have several big players investigating using our platform and software for boosting their efforts in the development aid space. Maybe we are doing something right.

a hosted version of Firefox would be pretty meta

Those don't use Linux kernel? Cmon.

I see at least two people didn't understand my comment. The point of the post was that you can make money by finding some useful open source software and making it into a service. But Linux is already available as a service; that's why I said try again.