Arth Rich

Who believed in you first? Silicon Valley runs on that question. a16z's Erik Torenberg, David Booth, Josh Elman, and Olivia Moore on Cosign: Cosign is a curated professional network for the startup community. Profiles are built from endorsements, fundraises, and talent moves, with a private layer to signal who you'd fund or hire. Erik ran a small version of this seven years ago, emailing a few hundred people and asking each for one person to watch. One of the answers was Russell Kaplan, then a 22-year-old engineer at Tesla, now president of Cognition. Olivia on why this matters: "The most valuable data in all of Silicon Valley is who has conviction in who." Investors chase it every day and still struggle to find it. An engineer choosing between five offers has almost no way to get it at all. Paul Graham cosigned Sam Altman in 2009, six years before OpenAI was founded. Ryan Hoover cosigned Erik early at Product Hunt. Silicon Valley has always run on cosigns from people whose word carries weight, and until now nobody kept the record. The conversation closes on the question of why anyone would share their alpha. David's answer is that the person you cosign today is the one raising a round in two years, and when they do, they remember who believed in them first. 0:55 Twitter as a credential 3:05 Silicon Valley is a race to discover talent 4:10 The 3 questions on every Cosign profile 5:45 The email that found Russell Kaplan at 22 6:15 Conviction is the scarcest data 9:50 Why Cosign is free and strictly positive 11:05 Seeing things before the market does 13:00 Sending private "I'd fund them" signals 18:35 Endorsements that don't vanish 23:05 Recognition for the unsung engineer 29:40 Building LinkedIn Jobs in 2004 34:25 AI made human endorsement scarce 36:45 Why nobody has disrupted LinkedIn 42:10 Your Cosign profile may already exist 46:25 Silicon Valley always ran on cosigns 48:10 "Why would I give away my alpha?" YouTube: youtu.be/-ywZlfznTa4 @eriktorenberg @davidbooth @joshelman @omooretweets