Understanding the Billboard Charts

Every musician knows that a spot on the Billboard Charts means that they’ve made a name for themselves. These statistics are read by entertainers like the Holy Bible. There are different charts for best single, best album and best digital album as well as divisions among those categories for different genres of music. These charts are updated weekly.
It’s important to realize that actually calculating these statistics is very difficult, and for the most part, unreliable, especially when it comes to radio play and physical CD sales. This is especially true for the “Top 200” chart, which ranks the top 200 albums, because of the wide scope of albums that have to be covered. Another grey area of the Billboard charts is the list that ranks the most successful artists. This is because only sales of full albums are counted towards measurement of an artist’s success, and therefore the amount of singles sold off of the album, which can often be higher than sales of the album itself, are not counted. Clearly, illegal downloads aren’t counted towards Billboard’s reports, and neither are singles and albums bought off of Amazon and Napster, although those purchases are legal. However, these illegal downloads play a major part in spreading the artist’s music around and so wouldn’t it contribute to an artist’s success?
There’s a chance that an artist may not make the charts because of the lack of physical album sales regardless of how many digital downloads it receives on the radio and on the unaccredited websites. Therefore, the way Billboard is constructed leaves a lot of room for inaccuracy.