>I wonder if there's going to be a market developing for services that look like current services, but actually cost money somehow. Probably a billion-dollar-level opportunity for figuring out how to charge for a Facebook or Google or Twitter a couple of bucks a month.

You're really overestimating people's willingness to pay for a service that's already free and convenient. There's really no good comp for tens of millions of users switching from a free service to a paid service just to avoid ads/conspiracy theories.