Social Audio Apps Are Having a Moment—Is It All Talk?

Emerging social-media apps that feature voice conversations are gaining users and drawing multimillion-dollar investments, while the biggest platforms are exploring their own foray into audio-chat features.Emerging social-media apps that feature voice conversations are gaining users and drawing multimillion-dollar investments, while the biggest platforms are exploring their own foray into audio-chat features.Read MorePAIDWSJ.com: US Business