I WAS SITTING in a bar recently when a song came on that I almost, just almost, recognized. Ten years ago, my inability to suss out this track would have gnawed at me for hours, but thanks to the now-classic iPhone app Shazam, I could instantly deduce it was “Making Plans for Nigel” by British rockers XTC. I wondered, not for the first time, why Shazam’s functionality hasn’t infiltrated the rest of our lives, specifically our quest for clothes. Often, I’ll see an item online—say, the three-pocket, lightly distressed chore jacket that David Beckham wore on “The Late Late Show with James Corden” (pictured above)—and wish...