What's in a name, really? CSC Holdings isn't a holding company at all -- it's the main operating subsidiary of Cablevision Systems Corporation, one of the top US cable and entertainment companies. Its core business is centered around its cable television network that serves about 3 million customers in the New York tri-state area under the brand Optimum. Another nearly 3 million viewers subscribe to digital cable under the iO brand. Optimum offers high-speed Internet access and digital phone service to about 4.5 million cable customers. Its services are sold individually or bundled -- combining cable TV, Internet, and digital phone. Chairman Charles Dolan and his family control 70% of Cablevision's shares.