Short answers, pulled from the story.
The first weekly album chart in American music history began on the 24th of March 1956 with Harry Belafonte at the top. His album simply titled Belafonte was the inaugural number one entry on what was then called Best-Selling Popular Albums.
The chart started as Best-Selling Popular Albums in 1956 and eventually settled on its current title Billboard 200 on the 14th of March 1992. It underwent multiple name changes including Best-Selling Pop Albums and Top LPs & Tape before reaching its final designation.
Billboard began relying on data from Nielsen SoundScan on the 25th of May 1991 to track actual sales data from approximately 14,000 music sellers. This computerized system replaced manual reports from record stores to provide a more accurate and transparent picture of what Americans were actually buying.
The catalog limitations were lifted starting with the issue dated the 5th of December 2009 following the death of Michael Jackson on the 25th of June 2009. This surge in sales for catalog albums forced Billboard to reconsider its rules and allow all albums to chart regardless of age.
The Rolling Stones hold the record for the most top 10 albums on the Billboard 200 with 38 entries. They also became the first act with newly charted top 10 albums in seven different decades when Hackney Diamonds debuted at number 3 on the 23rd of October 2023.
The 18th of January 2020 marked another major shift in the Billboard 200's methodology as Billboard began incorporating video and audio data from YouTube. This update included visual plays from streaming services like Apple Music Spotify Tidal and Vevo to reflect the growing importance of visual media.