A few weeks ago, Zillow, one of the leading real estate listing sites, made a surprising announcement: it was going to enter the business of flipping homes, the process of buying a home, fixing it up and quickly reselling it. This immediately raised two questions in my mind: why and why? First, good things generally don't happen when you as a data platform or provider give up your market neutrality. No matter the specifics, you are putting yourself in competition with your customers. That means ...