Clubhouse is a social audio app that allows users to join virtual "rooms" and communicate with others through audio. The app's main feature is real-time conversations in rooms divided into categories based on privacy levels - open, social, or closed. Users can create and moderate rooms, invite speakers to the stage, and raise their hand to speak. Clubhouse also offers scheduled events, user communities called "clubs" centered around common interests, and a messaging feature called "Backchannel" for text interactions.