Invitation links have been flying around Silicon Valley the past few days to an exclusive app that’s a combination of voice notes and Twitter, called Airchat. Airchat, still limited to an invitation-only audience, is the latest app being hyped in tech circles, and comes from AngelList co-creator Naval Ravikant and Brian Norgard, Tinder’s former chief product officer. It looks somewhat like a Twitter feed upon opening with blocks of text. They’re transcripts of voice notes posted by users, which ...