CoStar Group continues aggressive posture toward Zillow Group Andy Florance, the founder and CEO of CoStar Group, which has aggressively jumped into the residential real estate portal arena with its recent purchase of Homesnap and Homes.com, has developed an aggressive tone toward Zillow Group. His recent interview with Brad Inman at Inman Connect revealed how he’s hoping to position his firm’s real estate play in relation to the nation’s dominant portal. A backdrop to the conversation was Homesnap’s October launch of a New York City portal, Citysnap, that will compete with Zillow-owned New York City portal StreetEasy. While Zillow Group sells advertising and leads to agents for placement on other agents’ listings, CoStar Group has a focused strategy of only placing the listing agent’s contact info on listings on its sites.