Excited to introduce @Cosign: the curated professional network for the startup community: cosign.co Our goal is to create the following: - A comprehensive startup directory of investors, companies, and operators, including what they worked on and who they worked on it with. - Cosign graph: Who shaped your career? Who were you actually in the trenches with? Who would work with you again? Who thinks you’re someone to watch? - Durable reputation: Great endorsements happen every day on X and disappear into the feed. Cosign attaches those signals permanently to people and companies. - Discovery: Who are the best fintech angels? Which AI companies should I watch? Who are the best designers? - Intent network: Privately signal “I’d invest in them,” “I’d hire them,” “I’d work with them,” or eventually even “I’d acquire this company.” Match people when interest exists on both sides. Imagine if Wikipedia, LinkedIn, and OG AngelList had a baby. Though Cosign is a community, not a business. In order to join, you need to be cosigned. Or you can apply directly. David Booth and I started this idea 7 years ago but didn’t have the firepower to make it work. Now we do. No one has really touched LinkedIn in 20 years. Excited to take a swing. cosign.co

Announcing The Horowitz Andreessen Academy. The internet made it possible to know anything. AI makes it possible to do anything. The best assignments now are problems so hard they cannot be solved without AI. The Academy courses follow the same logic and will be taught by world-class leaders. The most talented young people today rarely have their sharpest peers within walking distance. Their network is online. Those networks are real, but they're thin. The next generation will not be taught the way the last one was. The Academy is built for that world, and it begins in San Francisco. If you're young, hungry and love building things, apply for the Founding Class Fellowship.