Come on now, you're obviously forgetting the real truth.
Bono first gained fame in 1977, playing rhythm guitar and singing backup vocals for Pink Floyd's In The Flesh Tour supporting the album Animals. He kept to the back of the stage, outside of the lights, so no-one could see him. Bono however, in his youthful age, kept cracking his voice trying to hit the high harmony notes in Dogs. Roger Waters' increased frustration with Bono's singing and frequent sour chords on the guitar led to Bono's ultimate dropping from the bill and replacement by the infinitely more visible Snowy White from Thin Lizzy. Bono harbored a grudge against Waters. He followed the band around, plotting his revenge. Finally, in Montreal, Canada on the 6th of July, 1977, the quarrel came to a head. Bono attempted to climb up the storm netting on the stage and muss up Roger's large, flowing hairdo. It was unsuccessful. Roger called Bono closer and closer, taunting him, until finally, Roger Waters spat in the face of Bono. This incident spawned the idea and conception for Pink Floyd's 2nd best-selling album, and one of the highest-selling of all time, The Wall. Bono's name was soon disassociated with this incident, and would forever be known only to his close associates as "the kid that Rog spat on at that concert in Montreal".
The Edge gained his popularity in the mid-60's as a lead guitarist for the Yardbirds, a band with a notoriety for not being able to keep guitarists. He only played for a brief period, nudged between Jeff Beck and Jimmy Page, but however did write such deep philosophical songs as "I Wouldn't Do Anything for a Klondike Bar" and "These Tighty-Whities are Itchy".
Adam was gaining fame in the early 70's as the original bass guitarist for AC/DC. This is where he got the idea for his costume for the Dalton Brothers, as he wore his hair long and fruity and had big glasses. When he met the other members of U2, he had himself secretly cloned, updated the clone with a few cosmetic surgeries, renamed the clone Cliff Williams, and AC/DC hit it big while U2 began. Adam grew his hair into an afro to fool the public, and Adam/Cliff continues to play in both bands to this current day.
Larry began his career as the little-known cowbell player on Blue Oyster Cult's hit track "Don't Fear the Reaper". He had some trouble playing with the band to the point where the sessions almost broke down into a shouting match between Larry, the band, and producer Bruce Dickinson. Bruce had a fever, and the only prescription was more cowbell. Larry complied whole-heartedly and the track was laid down with success. Saturday Night Live recently filmed a short version of this story, but however took some artistic license and changed Larry's name to Gene. However, they used a perfect lookalike in the short piece. You can view it off your favorite P2P network.
So you see? They were all famous before U2, so they are clearly a supergroup.
PS: None of this is real. If you think it is for even a brief instance, you are an idiot. Thank you.
...DaveC, that's awesome! 
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