In this era of streaming and free music, it can be difficult
to measure an artist's commercial success. But even though many fans are more
likely to listen to an album for free instead of buying it, sales are still a
major barometer of achievement in the music industry. In February, Michael
Jackson's iconic 1982 album "Thriller" — the top-selling album in
history — solidified its notoriety by hitting 33 million sales in the U.S.

With this in mind, PrettyFamous, an entertainment data site by Graphiq, found the best-selling
artists of the millennium using data from the Recording Industry Association of
America's (RIAA) database on gold and platinum single sales.

To measure the modern top-selling artists, PrettyFamous only
considered digitally downloaded singles, since digital sales did not begin to
impact the recording industry until the turn of the century. In case of a tie,
they favored the artist with the higher number of diamond certifications, then
multi-platinum, platinum and gold for all singles, not just those that were
digitally downloaded. Where ties still existed, they were broken by 30-day
Wikipedia page views — a proxy for notoriety.