Have you read any of them? (Many are digitized.) That is longform text more akin to the early-millennium blogosphere than modern social media. Moreover, the USA's early pamphlets were at a time of lower literacy rates and limited print runs, and reading one could involve real social interactions, not like screen-mediated ones, because one might also be reading out loud for one's fellows.

Martin Luther's 16th-century triumph was not in nailing his theses to the door, but having Gutenberg to distribute the pamphlets produced by him and his colleagues, far and wide, outstripping any measures to control or rein them in.