Jeff almost answered my comment in his response to Jet. In this response, he asked something to the effect of, Why does it make a difference if an artist is selling albums or singles or ringtones?
The answer is because the Nielsen numbers are claiming an increase in “music purchases” with no regard to the value of what is being purchased. By these metrics, an album is equal to a single and two singles outweigh an album. In terms of revenue, however, a single is only 1/10th of an album.
The rest of Jeff’s arguments make sense, but the Nielsen numbers are not comparing apples to apples, and using these numbers as a basis for anything is highly misleading.