Ask Billboard: What Are the Billboard 200's Longest-Charting Albums Ever?
By Gary Trust

A look at the chart's history reveals that Johnny Mathis and Metallica aren't so different after all. Plus, analysis of Alanis Morissette's sales and the new On-Demand Songs chart.
Ask Billboard is updated every week. As always, submit your questions about Billboard charts, sales and airplay, as well as general music musings, to askbb@billboard.com. Please include your first and last name, as well as your city, state and country, if outside the U.S.
WHAT ARE THE BILLBOARD 200'S LONGEST-CHARTING ALBUMS EVER?
Hi Gary,
This past week has been a historical one for the





