The Led Zeppelin guitar riff seems like a pointless garnish on an otherwise pretty standard and safe sounding dad-rock song. It's not like The Edge took the Zeppelin influence and really ran with it, following it to some crazy dimension...to me it seems almost like an afterthought, like the song was so uninspiring and faceless, they needed something to wake you up every minute or so. Why not inject a cliched sounding Zepellin riff. I mean, that riff sounds like Jimmy Page warming up on stage. It's a boring riff that doesn't go anywhere. It doesn't excite me. It doesn't make me want to ROCK OUT! It's just like "ohhhh that's The Edge referencing Led Zepplin, this is what passes for 'edge branching out' these days."
Now it's time for a little pretensiousness:
If i was in that room the day Edge came up with that riff, I would've said: "okay, you done having fun? Good! Now I want you to REALLY fucking get down with it!!"
And then i would've slipped Bono some drugs, and said "forget about who you are, take this pen, take this paper, and write, dammit! Give us something intense! "Little old lady???!?!?!?" (i taze him until he is drained of all cornball lyrics)