This song came at a transitional stage in the Billboard charts, giving it a very strange chart history. In the '90s, many record labels refused to sell certain singles in America so that folks would have to buy the album to get the song. Promotional singles were sent to radio stations, which dutifully played the hits in the order they were received (videos were released accordingly).
Billboard's Hot 100 chart stipulated that a song be sold as a single to be eligible, so a song could be saturating the airwaves, but have no presence on the Hot 100. Billboard's Airplay chart kept track of radio play, and on August 1, 1998, "Iris" hit the top spot, where it would stay for 18 (non-consecutive) weeks. The week of December 5, 1998, Billboard eliminated the Hot 100 restriction on songs being sold as singles, and "Iris" appeared at #9, months past its popular peak. There is little doubt that "Iris" would have made #1 if it was eligible from the start on the Hot 100; the #1 song throughout August was "The Boy Is Mine
" by Brandy & Monica, which had already held the top spot for two months.