Clubhouse had been available only on Apple devices, and its user base is likely to expand more rapidly with addition of a version for Android, the mobile operating system that runs about 70% of the world's smartphones.

The app probably would have grown faster if it didn't require people to invite others to use it. However, that limitation gives the startup more time to set up the infrastructure to host millions of live chats at the same time.

The startup this week set up an "accelerator" program that provides monthly stipends, equipment and promotional services for independent creators to produce more content for its platform. In announcing the Clubhouse Creator First program, it cited programming like "News News News," which covers daily headlines every day five minutes at a time, and "The Lullaby Club," which provides "a sonic bubble bath" to help people relax and get to sleep.

For existing publishers, there is an opportunity to extend their audio production capabilities from podcasts into live audio chats.

Unlike podcasts, which can be time-shifted for on-demand listening, Clubhouse is focused on providing the immediacy of a live production. The format also allows for sponsorships, such as host-read spots, though the audience is likely to be much more limited until the platform expands. Still, it may be worthwhile to experiment with the format, possibly as an extension of live programming by publishers whose in-person events have been impeded by the pandemic.