Thanks Amy. The book analogy seems a bit inapt. Written expression is ancient, e.g., Chauvet cave, and its presence and spread was a gradual process. Sure, the printing press and literacy via public education were big deals, but they were gradual events using known technology. Social media is new and happened overnight. Second, there's a world of difference between static expressions like the Bible and informational websites, whose content is largely if not entirely controlled by mods, and social media, whose content is user-generated in a far more laissez-faire context. I'd think these distinctions from books would make the impact of social media eminently subject to analysis.

Anyway, thanks for the answer, I'll check out your link!