Spontaneous social apps that let users join video, voice, and chat rooms on a whim have become popular under lockdowns, like exclusive voice chat app Clubhouse (Josh Constine/TechCrunch)

Josh Constine / TechCrunch:
Spontaneous social apps that let users join video, voice, and chat rooms on a whim have become popular under lockdowns, like exclusive voice chat app Clubhouse  —  Forget the calendar invite.  Just jump into a conversation.  That's the idea powering a fresh batch of social startups poised …