Beginning this week, Billboard will include audio and video streams from services like Yahoo! Music and AOL in its formula for the weekly “Hot 100” singles chart. The top songs will still mostly be determined by radio airplay (55 percent of the formula) and digital downloads (40 percent), with streams accounting for five percent. For now, only Yahoo! and AOL — two of the biggest online streamers — will be included in the calculus, but a Billboard rep says other services, like Rhapsody, will be included soon. It’s hard to say if the move will have any immediate impact — this week’s number one, Sean Kingston’s “Beautiful Girls” is big across the board — but it certainly is a move toward better reflecting what people are listening to.