Realogy franchisors Century 21 Real Estate and Coldwell Banker Real Estate have re-upped as members of the Real Estate Network, a program that lets brokers and multiple listing services send their listings to the national websites operated by franchisors and other real estate groups. ListHub announced last week that the two other founding REN members - Re/Max and Realty Executives - had renewed their membership and that an independent brokerage network, Leading Real Estate Companies of the World, had joined.