The residential real estate brokerage industry gained a significant new player when CoStar Group (Nasdaq: CSGP), the dominant commercial and multifamily real estate marketing and portal operator, acquired Homesnap and Homes.com. The aggressive, well-operated giant has plans, and the resources and experience, to create a residential real estate sales marketplace that rivals Zillow and realtor.com. This chapter analyzes the company’s key components, how it operates and its dive into the residential real estate industry.