Several top musicians should be writing the current crop of American Idol contestants a thank-you note right now -- they've all experienced huge increases in their digital sales after the kids performed their songs on the show.  Take, for example, John Legend.  After contestant Alex Lambert sang his song "Everybody Knows" on the show last week, sales increased a whopping 2,938%.  And after Katelyn Epperly sang COLDPLAY's "The Scientist," sales of that track shot up 844%.

Other beneficiaries of the Idol effect include Matt Nathanon, whose song "Come On Get Higher" enjoyed a 293% sales boost after Tim Urban sang it, and Hinder, whose "Lips of An Angel" soared 350% after Lee Dewyze sang it.  Creed's "With Arms Wide Open" jumped 204% thanks to Michael Delamar, and John Park's performance of John Mayer's "Gravity" gave it a 172% sales boost. 

Next week, we'll find out how, for example, Crystal Bowersox's version of Tracy Chapman's "Give Me One Reason" affected that song's sales.