"Walk on" could've been the next "One", had they released it as a single in late 2001. (Let me make it known that I'm not talking about the single you buy in the stores. I'm talking about radio singles. In the U.S., the only singles we get are imports.) Unlike everywhere else, we in America got the Walk on video/radio single in early 2001, when Beautiful Day was still riding high, and there wasn't room for two U2 hits on the radio. "Stuck in a moment" was released as a single in the U.S. in late 2001, and as a result of 9/11, it became a very popular song, dare I say "OVERPLAYED". But if "Walk on" had come out in September of 2001, it definately would have been the next "One", or possibly even bigger. "Walk on" did become a post-9/11 hit, but not as big as it could've.
*Bear in mind, I so wish that the events of 9/11 would have never happened. I don't want you to think I am glorifying a tragedy by discussing how it could've effected a song on the radio charts. But I was just saying how "Walk on" could've really become a HUGE hit after the events of 9/11/01, because people would've really identified with it, and found comfort in it. But if 9/11 had not happened, we'd have all those people with us. Oh....and some U2 song wouldn't have done well on the charts. I think those would be ideal circumstances.