a16z’s @david__booth on the 7-year-old prototype behind Cosign, why it petered out, and what changed enough for a month-old team to ship it now: "How do you find people before the world knows they're great? That's the core thesis. Seven or eight years ago, @eriktorenberg and I built a first version of this. Then the pandemic happened and it petered out." "About six weeks ago we realized that maybe the time is now. The ability to use AI to generate out the profiles, to aggregate cosigns that…