Editor’s note: Aileen Lee is founder of Cowboy Ventures, a seed-stage fund that backs entrepreneurs reinventing work and personal life through software. Previously, she joined Kleiner Perkins Caufield & Byers in 1999 and was also founding CEO of digital media company RMG Networks, backed by KPCB. Follow her on Twitter @aileenlee. Why do investors seem to care about “billion dollar exits”? Historically, top venture funds have driven returns from their ownership in just a few companies in a given fund of many companies. Plus, traditional venture funds have grown in size, requiring larger “exits” to deliver acceptable returns.