In short, they try to save the Internet from being run by a few corporations or governments. So, minus cape, they're trying to do superhero things that are often at odds with the biggest companies in the world. Whether they succeed in that with any given project is up for debate, of course.

So far, Firefox phones have been a flop. Personally, I want one, because I care about privacy and I care about the open web, but I don't really want a shitty $25 phone. This news is good for me, but I don't know what it says for Mozilla's vision in the mobile market.

I've heard people suggest that Android took a while to catch on...but, it really didn't. By the time Android had been on the market for a year, it was clear (to me, anyway) that it would become the dominant player for many of the same reasons Wintel became the dominant desktop platform. Firefox OS doesn't have much to show for the time they've been on the market. It was never even clear to me I could buy a "real" phone (i.e. not developer phone) in the US running FxOS.