Advertising does not make content free. It merely externalizes the costs in a way that incentivizes malicious or incompetent players to build things like Superfish, infect 1 in 20 machines with ad injection malware, and create sites that require unsafe plugins and take twice as many resources to load, quite expensive in terms of bandwidth, power, and stability. It will take a major force to disrupt this ecosystem and motivate alternative revenue models. I hope that Mozilla can be that force.
Emphasis mine. I think this talk of externalizing costs is something that's surfacing a good deal more than it used to — or at the very least, I'm getting exposed to it more often, thanks to reading up more on things like discussions of economic theory and practice.
One of the things about over-the-air, commercially-supported TV was how its free content came at multiple costs, most of them hidden from the viewer. It cost you your time and attention to sit through commercials (and even editing them out on the VCR or zipping through them at high speed were only partial solutions); it cost network censorship and advertiser pressure; it cost a great many things you might not have been aware of, because they'd all been externalized in ways you might not ever encounter on your own. With most any ad-supported service, the end user is the product that is sold to marketers; Twitter and Facebook didn't invent this sort of thing, but they are steadily refining it in ways its original creators never could have imagined, let alone executed on.
Exercise for the reader: look at all the things you consider "free" without a thought, and apply some analysis as to how their costs may simply have been shifted back to you in unconsidered ways. Bonus points awarded for determining how this shifting of cost has further devalued other things that do sport price tags ...