U2, formed in Dublin in 1976 and still an Irish rock band, at first consisted of Bono (vocals), The Edge (guitars), and two other guys (bass and drums, respectively). After 1993's Zooroopa, the band reorganized its personnel; the current lineup is now Bono (vocals) and some other nameless guys (non-vocals). Bono has cited both "a need for change" and "a stronger focus on charitable endeavors" to be the driving forces behind the reorganization, but those other guys insist it's just another way of "Bono being, like, a huge dick to everyone else".
Critics are inclined to agree with these anonymous bandmates, though the public at large finds Bono's scenery-chewing douchebaggery appealing. Indeed, many fans don't see Bono as a douchebag, but as somebody who's "stylish", "cool", and "noble". Experts have said that Bono's rising popularity with the common people indicates that the public itself has become increasingly douchey and arrogant.
The radical change in the band's image over time can be seen as U2 "evolving" from playing hard-hitting rock music to whatever it is today. Essentially now playing Bono's melodious voice over and over again over all sorts of weird orchestra music and some sort of muddled-reverb once identifiable as "guitar", the sound can be compared to a seal slaughter recorded in slow motion.
U2, one of the most successful rock bands of all time, has somehow sold over 150 million records worldwide, won 22 Grammy Awards, been inducted into the Rock and Roll Hall of Fame and, due to an administrative error, was named "Breakfast Cereal of the Year 2009".