A few years ago Clear Channel was buying up thousands of American radio stations, becoming the giant of the business. But now it’s splitting off some of its enterprises as the aggressive growth backfired. “In the past year alone, its stock is off 25%, to about $29, even after the company bought back about 10% of outstanding shares starting in April, 2004. That’s a steep drop from about $80 a share at its buying peak in 2000. The formerly cocksure Clear Channel is a humbled enterprise.”