A year ago, before Billboard magazine switched to its computerized system for tracking the actual airplay and record sales of hit singles, a song could not even make the Top 20 unless it had been a strong performer on "official playlists" submitted each week by a panel of radio stations. But now, the scene has changed so much that a record can move right into the Top 5-and even all the way to No. 1-with very little radio support.

That's bad news for Mariah Carey's big ballad "I'll Be There," which for nearly two months has dominated radio airplay but so far has had just two weeks at No. 1. This week, "I'll Be There" again was No. 2 behind Sir Mix-A-Lot's rap powerhouse, "Baby Got Back," which still hasn't cracked the Top 10 in airplay but nonetheless swept to a third straight week as the overall champ.