I've never quite understood why 1999 is the inevitable comparison. Perhaps because of the emotional reaction it gets (clicks) when you use it.<p>2005-2007 is the more accurate comparison. The acceleration of asset bubbles in both real estate and - to a much lesser degree - the stock market leading up to the great recession (and I'm not implying there will be a replay of the housing bubble). It involved a gradual but significant venture capital increase from the bottom years of 2002-2003, and public valuations expanded significantly.<p>From roughly Jan 2003 to Aug 2007, the Dow went up about 75% and finally surpassed the highs made during the dotcom bubble. Companies like Google IPO'd during that run. There was also a dramatic China bubble during that era.<p>Valuations were elevated by quite a bit, but not like 1999. Venture capital was flowing freely, but not like 1999. The stock market had gone on a huge run, but not like 1999.<p>The downside to the currently elevated financial environment, will be tightened liquidity, harsher terms, and lower public multiples. That means, conceptually, instead of Facebook having a 90 PE ratio, they'll have a 40 PE ratio.