"Iris" has contributed greatly to the band's success. Besides becoming one of the biggest alternative rock staples of its time, "Iris" also remains one of the biggest crossover hits in the history of popular music, crossing over from modern rock radio to pop and adult contemporary radio, reaching number one on all of these formats and becoming the most played song of 1998 for all formats. The song reached number one in Australia, Canada and Italy, number three in the United Kingdom, number nine on the US "Billboard" Hot 100, and has become one of Ireland's best-selling singles of all time. "Iris" is the Goo Goo Dolls' signature song and has received critical acclaim, being described as an "ubiquitous" staple for the band's live sets.