Technology How the Internet Uses Nostalgia Long-lost memories pop up in music recommendations, personality -- House are selling Greek yogurt. Boyz II Men recently made a cameo on How I Met Your Mother. This year's Super Bowl featured, of all people, Flea. We are having a moment of '90s nostalgia, occasioned in part by millennials (or The Youths or Those Kids or whatever you want to call them) who are aging into adulthood and therefore eager to relive their -- *** Nostalgia, the copious literature on it suggests, comes in two basic forms. One is organic, the kind that washes over you when you see an old picture of yourself and your cousins, aged 7 and 9 and 10, giggling -- Dawson’s Creek's Joey and/or Blossom's Joey, appropriated to arouse a vague sense that we have lost something as we’ve moved, inexorably, into our future. This form of nostalgia is usually invoked, in one way or another, to sell us stuff. You could, because of that, dismiss its validity (fauxstalgia?). But it will live on, inevitably, because media producers know exactly what advertisers have long understood: that nostalgia, like sex, sells. The products of that basic insight, whether they're movies or TV shows -- Lebowski. Nostalgia, under the stewardship of the Internet, has been made nimble. As market goods, however, these products can also be recursive: Mad Men -- While, sure, commercial culture is commercial, it’s also notable how ambient nostalgia has become. The memorial-industrial complex ensures that our past—our collective past—permeates our present. That complex markets directly to memories that are shared, across generations and -- to realize the vague-but-also-urgent goal shared by many social networks and services: user engagement. "For almost everyone,” Sung says, a nostalgia-focused Spotify story “usually triggers some sort of strong emotion. Sometimes it's, 'Wow, I totally forgot that song. Thanks so much for reminding me of it.' Other times, it's more like, -- Either way, though: engagement. And an experience of the past that is customized—if not to a person, individually, then to that person's generational demographic. Spotify’s interpretation of nostalgia, in that sense, is pretty much the opposite of The LEGO® Movie’s or Mad Men's or that of Kraft-by-way-of-the-Ninja Turtles-by-way-of-Vanilla -- *** Spotify isn’t alone in its use of nostalgia as a marketing tool. Social networks in general, you could argue, are implicitly—preemptively—nostalgic, combining our pasts and our -- Networks, however, are also experimenting with more explicit forms of nostalgia-baiting. Earlier this month, Facebook rolled out “Look Back” compilations that collect users’ most-liked photos, statuses, and life events into an easily viewable video. (These collections come in -- Even Pinterest, which is most commonly associated with future-oriented and aspirational image-collecting, makes use of customized nostalgia. Gabriel Trionfi, Pinterest's user experience researcher, is a psychologist by training, and he points out that the flip side of anticipation—one of the emotions Pinterest uses to generation its own version of user engagement—is, yep, nostalgia. Journalists have long recognized the same thing advertisers have, which is that nostalgia is an extremely efficient tool for selling stuff. “Nostalgia is a known way to boost people's mood,” Trionfi told me. It allows people to live (and re-live) “something familiar, something they remember, a positive emotional experience.” On Pinterest, he points -- past. Nostalgia, at its most basic level, requires access to memories—and there is, of course, no better archive than the Internet. The social networks that are becoming increasingly synonymous with our experience -- The good feeling is growing. Many media outlets ("content producers," you could call them) are selling nostalgia in one form or another: There’s Retronaut and @historyinpix and the many similar—and controversial—features dedicated to the resurfacing of the past. There’s New York magazine’s late, great “Nostalgia Face-Check” series. Yesterday, Wired—known mostly for its reporting on the future—published a list, curated by Questlove, of the top hip-hop tracks of the ’90s. -- This is all fairly unremarkable; journalists have long recognized the same thing advertisers have, which is that nostalgia is an extremely efficient tool for selling stuff. But media outlets—especially the ones that are merging technological prowess with journalistic—aren’t just leveraging our soft enthusiasms for the past; they’re also taking a platform-focused approach to that work. They, like the social networks, are trafficking in targeted nostalgia. Take Buzzfeed’s ever-more-ubiquitous quizzes. “Which ‘90s Movie -- people who fit those demographics. The upshot of all this? Nostalgia no longer comes in one-size-fits-all, and that size is no longer “large.” Nostalgia, under the stewardship of the Internet, has been made nimble. Our tenuous relationship with the past can now be customized and made relevant, in the manner of a