Announcing Cosign. Silicon Valley knows people by watching other people know them. One person's visible belief becomes a signal to someone else, and the network updates its priors. Ascendancy is a game of two moves: self-made wins and high-status vouches. The earlier someone is in their trajectory, the less proof there is to go on, and the more meaningful the vouch. Belief compounds. People used to earn status through rites of passage like graduating college and landing prestigious jobs.…