Very cool! There seems to be at least one big missing piece: D. E. Shaw & Co. That would have spun off Juno via Charles Ardai (bought by NetZero?), Amazon via

Very cool! There seems to be at least one big missing piece: D. E. Shaw & Co. That would have spun off Juno via Charles Ardai (bought by NetZero?), Amazon via Jeff Bezos, Fog Creek for Joel Spolsky, Farsight Financial Services, and probably a few more that I can't remember just now. (Art of Problem Solving and Two Sigma are significant but aren't in tech).