I thought this was a crucial observation by Andrew Chadwick about the tendency to conflate ‘online’ with ‘grassroots’. It’s from pg 67 of this The Hybrid Media System. It lingers on in the platform imaginary in a way reinforced by the tendency to conflate the demotic and the democratic:
One problem with the “convergence culture” approach is its equation of “online” with “grassroots” activism. The rise of online media elites, the increasing use of the logics of online media by those working in older media together with the ongoing intervention by non-elites in the construction of political news and information brings this dualism into question. When such large numbers of bloggers are now integrated into professionalized or semi-professionalized news production, when citizen activists are integrated into news-making assemblages through their participation as bloggers or Twitter and Facebook users, and when the vast majority of older media organizations have moved into the online environment, it is not always accurate to counterpose an online participatory culture against a centralized, top-down, broadcast media culture.