Buried in Time Warner's announcement today about giving away AOL to broadband customers were second-quarter results showing that the company's cable division had a 15 percent jump in revenues, to $2.7 billion. Cable was the biggest contributor to operating income, adding $1 billion. That's a 16 percent increase from last year. Guess where much of this growth came from? A jump in cable subscriptions. Time Warner said average revenue per basic cable subscriber rose 14 percent, to $91. Some of that came from higher demand for premium services like high-speed data, digital phone and digital video services. Old Adelphia customers who are about to become new Time Warner Cable customers will likely see an improvement in cable offerings and customer service, but keep your wallet handy.