The document summarizes Anita Elberse's investigation into Chris Anderson's long tail theory. Elberse reviewed sales data from online music and video retailers and found that while niche products made up the majority of titles available, they accounted for a small share of total sales. She also discussed William McPhee's theory of exposure and double jeopardy, which found that popular products tend to be consumed by more users. The document concludes by providing advice to producers and retailers on how to approach the long tail.