I've been impressed by Andreedsen Horowitz's approach of recognizing winners in large markets and putting large amounts of money to work. It's gutsy and smart.

However, I'm concerned about putting large amounts of money into startups that have yet to become businesses. An over-abundance of resources is often detrimental to realizing a vision and finding a market.

Anyway, I remain a fan of A16Z and suspect they've seen something compelling not yet visibile to the outside observer.