You can do too much due diligence. It's important to talk to the market and hear what it is saying. But you have to balance that with other things; the quality of the team, the product, the user experience, etc. You cannot rely alone on due diligence, particularly early on in the development of a company and a market.
Fred Wilson has been a venture capitalist since 1987. He currently is a managing partner at Union Square Ventures and also founded Flatiron Partners. Fred has a Bachelors degree in Mechanical Engineering from MIT and an MBA from The Wharton School of Business at the University of Pennsylvania. Fred is married with three kids and lives in New York City.