The Clubhouse app is re-introducing the thrill of a roomful of voices. But a grassroots version of the same phenomenon shook the phone companies nearly half a century ago. A recent article on Medium’s technology blog OneZero remembers how underground communities sprung up on the phone lines that crisscrossed the planet, meeting in secret communal gathering places that they’d discovered on phone networks. They’d “carved out communities, shared knowledge, and indulged in a larger spirit of exploration,” united by the thrill of discovering things together. Decades before the dawn of consumer internet services, it may have been the closest thing to going online.