Most of the venture funds are actually investing the money of pension funds and university endowments, not "rich people". "Rich people" - meaning recent tech multi-millionaires are driving an increase in angel investing, but they are not who's driving these 50x revenue multiples for later stage companies. If were to give anyone credit for these multiples, it would be Facebook. They've definitely inflated the value of companies that went out before them (Zynga, Linkedin, Groupon, Pandora) and have helped push up valuations of Dropbox and others. When $100bn is your ceiling for a "private" company value, psychologically it allows for much more aggressive private valuations. And it's likely that Facebook private valuation is an extreme outlier, not a "new normal", which will lead to a boatload of companies that have their highest valuation ever before they go public.