Nobody in Hollywood can keep a secret -- exceptDisney chairman Michael Eisner. He stunned both Wall Street and the entertainment industry when he announced this morning thatDisneywill acquire Capital Cities/ABC in a $19 billion merger. The deal would be the second-largest takeover in U.S. history (behind the $25 billion takeover of RJR-Nabisco in 1989) and the largest ever in the media business. Getting hitched to family-friendly Disney may mean top-rated ABC will see its competitors exploiting new counterprogramming opportunities. "I think ABC will probably steer away from the more lurid programs, which might make the other networks go in that direction," said Time's Jeffrey Ressner in Los Angeles. The merger, already approved by the boards of both companies, is expected to pass regulatory muster as well.