It hearkens back to "Elevation" from "All That You Can't Leave Behind" and "Even Better Than The Real Thing" or "The Fly" from "Achtung Baby". It's a statement song. The quintessential first single. Something that gets people to take notice a bit and not count out the boys just for being in or pushing their 40s or whatever age they are up to now.
It's a 25 year old band saying that they can still do it just like the 25 year olds pushing out hits today. And, it's the only song of it's kind on the album. I would have to say that not one song on the album pushes as hard as this does...has the rock feel that this single does. It's as though they made the song and then made it the first single just to make the statements above. "We're here. We fuckin' rock. And if we wanted to, we could bury you all with more songs just like this." But that isn't U2. They're more true to their music, themselves, and their fans than to just put out something that will sell. Something for the sake of being number 1. They don't seem to care about that, but they also know, with a sly smirk, that they don't have to worry about it either.
I'm pretty sure this song will open up their show each night on the upcoming tour. This is a hell of an opening track and one of my favorites from the album.