West Hollywood-based Citysearch announced today that it has hired on Christophe Louvion--the former CTO of Gorilla Nation Media--as its Chief Technology Officer and Senior Vice President of Core Products. Citysearch, which is owned by IAC, said that Louvion will be responsible for the firm's CityGrid's ad and content engine, plus its search and data platform. Louvian also previously served at BizRate.com and Shopzilla.