[Reprinted from my Red Herring blog, 2004]

Lists are the white noise of information. They're everywhere, and we all make them, but they're so familiar they escape our notice. What's on a to-do list is what matters; the list itself as a thing—as a way of organizing information—isn't worthy of attention.

This has been true for a couple reasons. First, lists are incredibly simple, yet incredibly versatile. They can represent anything from an inventory of goods to a set of tasks to be completed. Second, lists are functional things, tools to get a job done. It's what we can do with a list that matters, not the list itself. It's the message that matters, not the medium. Finally, lists aren't like literature. Everyone knows how to make them. There are no aesthetics of list-making, no such thing as a stylish or elegant list, no difference between a list made by Ernest Hemingway or your Uncle Ernie.

But to invoke the overused Marshall McLuhan phrase, the medium is becoming the message. In the online world, lists are starting to morph from tools for managing complexity, to tools for projecting identity. This transition reveals something about what happens when old and new information technologies converge.

Lists are as old as writing itself. Humans have told stories, woven myths, said prayers to gods and ancestors for tens of thousands of years; yet the oldest surviving written records (cuneiform tablets from ancient Babylon) aren't poems or religious texts, but inventories and records of commercial transactions. Why were these written down first? It's harder to remember a long list of goods than it is to remember a complicated story (though plenty of ancient writings—the Iliad and the Old Testament, for example—include some lists), and a lot less entertaining.

Fast forward to the last few years. Some of the most popular high-tech devices and features have been tools that let you manage complexity. The Palm Pilot, for example, was essentially a list manager: you could easily store and retrieve lists of people (stored in your address book), appointments (stored in a calendar), and things you needed to do (the aptly-named to-do list). MP3 players let you create playlists, carving your favorite songs out of an undifferentiated mass of music. Cell phones are so successful at managing the complexity of telephone numbers that they're virtually machines for making you forget phone numbers.

The pattern has continued with weblogs. Look on almost any blog, and you'll see a list of recent entries, and another list that takes you to archived entries, and another that organizes entries by category. Most bloggers also have blogdexes, lists of other blogs that they read or recommend. Then there is a dizzyingly varied—well, list—of other lists: lists of friends' Web sites, All Consuming lists of books or music, Feedroll lists of recent posts from other blogs, playlists grabbed from iTunes via Kung-Log, and others. At a certain point, these go from being tools to manage complexity to being something else: tools for projecting identity, for telling the world who we are.

Some lists have always communicated information about identity and social status. Invitation lists define who can get into a fancy club, seating at a hip restaurant, time with a busy politician. Wedding registries reveal a lot about a couple's tastes, and how much empty space they have in their kitchens. "Greatest" lists—lists of all-time greatest rock songs, movies, World Series games, what have you—reflect the judgment of their creators, and are designed to spark debate ("There's no way that 'The 400 Blows is better than Apocalypse Now!").

What's interesting is that we're now taking highly functional lists, and learning to put them to same purpose. This had its earliest online expression in e-mail. As David Brooks pointed out in a New Yorker piece, an "I've moved, here's my new address" message effectively, yet modestly, broadcast a sender's social connections. Cc:s to friends at whitehouse.gov, davos.org, and MITalumni.edu don't shout "I know everyone." They don't need do. Online blogdexes and All Consuming lists become displays of who you know, what you're reading and listening to, and where you've been: in other words, they become signals of who you are.

People can read and interpret lists. But so can software. And here's where services like recommendation agents, social software, and the "social bookmarks" manager del.icio.us make things really interesting. Such services take tens of thousands of lists—of what people have bought, who they say they're friends with, what they've read this morning—and look across them for interesting connections. People who bought these books also bought these; why don't you check them out? Your friends know these other people who you don't; maybe you'd like an introduction? Half a dozen other people have bookmarked this article that you figured only you'd be interested in; want to know who they are, and what else they've been reading?

The very modesty of lists is what makes them powerful in the digital world as both complexity management tools and identity projectors. People can wrap context around a list; programs can aggregate lists and find larger patterns and connections in them. I'd have as hard a time seeing bigger patterns in thousands of pages of purchase data as a computer would have in figuring out what kind of a person you are based on what your favorite albums are and what books you're reading.

The transformation of the list into an identity projector demonstrates something else pretty profound about modern life. More and more, we define ourselves, and understand each other, in terms of things that we do, rather than according to fixed categories of family, class, or background. It's a much more dynamic notion of identity than existed in centuries past, when you were defined—and your life determined—by family and social station. At the same time, the desire to belong to groups—to be part of something bigger than ourselves—hasn't gone away.

The brilliance of social software and recommendation agents, then, is that they allow us to still see ourselves as parts of something bigger, and to believe that we can always find like-minded souls no matter where we go or what we choose to do.

There's also a deeper lesson for futurists. One of the most powerful category of technological changes, the kind that have a simmering but profound effect on the future, involves small changes to really fundamental things. We're always on the lookout for disruptive technologies: they're splashier, they demand strategic responses by companies, and they embody the creative destruction of high-tech capitalism. But some of the biggest changes can come when you take something familiar, and tweak it just a little bit.

These small changes are especially worth following today because they can get big in a hurry. Connective technologies are amplifiers of social change, to paraphrase Howard Rheingold. Take something really familiar—like notes to friends, or lists of things—put them online, make them accessible to hundreds of millions of people, and the result can get nearly-instant, widespread social change. We've seen it with SMS, IM, blogging, and file-sharing.

There are plenty of other examples. You could make a list.