Zillow CEO expands on tech valuation Twitter storm By: CNBC.com News September 10, 2014 at 15:34 PM EDT Zillow CEO Spencer Rascoff launches a Twitter storm about tech IPO valuations as Alibaba road show kicks off. Read More >> Related Stocks: Amazon.com Facebook Google, Inc. TripAdvisor Twitter, Inc. Zynga Inc Cl A eBay