If you care what I think, you know that Twitter is just about the best way to learn what I’m paying attention to. I pass along tidbits of O’Reilly news, interesting reading from mailing lists and blogs I follow, and of course, tidbits from the twitterers I’m following. These are all the things I could never find time to put on my blog, but that I spray via email like a firehose at editors, conference planners, and researchers within O’Reilly. A lot of my job is, as we say, “redistributing the future” – following interesting people, and passing on what I learn to others. And twitter is an awesome tool for doing just that.

Like a lot of people, I tried out Twitter early on, but didn’t stick to it. Most of the early twitter conversation was personal, and I didn’t have time for it. I came back when I noticed that about 5000 people were following my non-existent updates, waiting for me to say something. With that many listeners, I thought I’d better oblige. (There are now close to 16,000.) I soon realized that Twitter has grown up to become a critical business tool, ideal for following the latest news, tracking the ideas and whereabouts of people who will shape the future of technology, and sharing my own thoughts and attention stream.

I thought I should outline here some of the specific things I find so compelling about Twitter, with suggestions about architectural features to be emulated by other internet services.

Twitter is simple. Twitter does one small thing, and does it well. Folks like Robert Scoble sing the praises of Friendfeed, which you could think of as twitter++. After all, it’s got comments and aggregation of data from multiple services. But despite its powerful premise, Friendfeed hasn’t dented Twitter’s growth. Personally, I don’t have time to wade through the comments; for me, Twitter is about quick hits, not about extended discussion. And while I love the promise of service aggregation, I tend to think that trying to marry it to commenting obscures its potential. Less is more. New services like peoplebrowsr are reframing service aggregation in a richer way, as a way of learning more about the people you follow, browsing the social graph. (Peoplebrowsr is still in alpha, but I think it has real potential as a social graph explorer, rather than as yet another people feed-reader.) Twitter works like people do. If I’m interested in someone, I don’t have to ask their permission to follow them. I don’t have to ask if they will be my friend: that is something that evolves naturally over time. If you’re a public figure like I am, the metaphor of mutual “friending” is truly broken. I get tens of thousands of friend requests from people I don’t know. Accepting would make it impossible for me to use a social tool to keep in touch with my real friends. Friend groups don’t really help. Twitter’s brilliant social architecture means that anyone can follow me, and I can follow anyone else (unless they want to keep their updates private.) Gradually, through repeated contact, we become friends. @ replies that can only be seen by people followed by both parties to a conversation create a natural kind of social grouping, as well as social group extensibility, as I gradually get more and more visibility into new people that my friends already know. Meanwhile, truly private direct messages are also supported. I don’t know who first used the term “ambient intimacy” but it’s a great description of what begins to happen on Twitter. I know not just what people are thinking about or reading, but enough about what they are doing that our relationship deepens, just like real-world friendships. People who follow me on Twitter learn that I’m making jam or pies, or gardening or riding my bike or feeding the horses, things that I’d never (or rarely, since I’m doing it here) share on my blog. I know a lot more about many of my professional contacts that makes them more into friends. And in the case of my family, who keep their updates private and visible only to a limited group of real friends, we can keep in touch in small ways that mean a lot. I get special moments of my wife or daughters’ day that we might not have shared otherwise. It’s truly lovely. Twitter cooperates well with others. Rather than loading itself down with features, it lets others extend its reach. There are dozens of powerful third-party interface programs; there are hundreds of add-on sites and tools. Twitter even lets competitors (like FriendFeed or Facebook) slurp its content into their services. But instead of strengthening them, it seems to strengthen Twitter. It’s the new version of embrace and extend: inject and take over. (Scoble recently noticed that 60%+ of his friends’ updates on Facebook actually came from twitter. And as John Battelle noted in a recent tweet, “I noticed now that my FBook status is updated with Twitter, I get responses in Fbook, but would like to see them here.” It might seem like a strength for Facebook to allow Twitter to update its status feed, but not the other way around, but I think Facebook will one day realize that Twitter has taken them over….) Twitter transcends the web. Like all of the key internet services today, Twitter is equally at home on the mobile phone. Even on the PC, I find myself using a separate client (Twhirl is an Adobe Air program) that provides a rich, alternate interface. Twitter is user-extensible.The @syntax for referring to users, hashtags, and whatever you call the use of $ as a special symbol for reference to financial instruments, were all user-generated innovations that, because of Twitter’s simplicity, allowed for third party services to be layered not just on the API, but on the content. Twitter evolves quickly. Perhaps because its features are so minimal, new user behaviors seem to propagate across Twitter really quickly. It’s a bit like the reason that fruit flies are used for genetic research: the short lifespan compresses the time for mutations to take hold. Perhaps a better analogy would be the speed of cultural evolution among humans compared to biological evolution. The most fascinating evolution happening on Twitter isn’t an evolution of the software, but an evolution in user behavior and in the types of data that are being shared. I saw this myself with retweeting, a behavior I picked up not from Twitter itself but from twhirl, the Twitter client I use. Because Twhirl actually has a button for retweeting, it seemed the most natural thing in the world to do it. I became one of the most prolific retweeters, figuring that I have more followers than most of the people I know, and that it would be good form to pass on the best of what they post. But it’s fascinating to see the growth of retweeting by others, even those not using twhirl.

In many ways, Twitter is a re-incarnation of the old Unix philosophy of simple, cooperating tools. The essence of Twitter is its constraints, the things it doesn’t do, and the way that its core services aren’t bound to a particular interface.

It strikes me that many of the programs that become enduring platforms have these same characteristics. Few people use the old TCP/IP-based applications like telnet and ftp any more, but TCP/IP itself is ubiquitous. No one uses the mail program any more, but all of us still use email. No one uses Tim Berners-Lee’s original web server and browser any more. Both were superseded by independent programs that used his core innovations: http and html.

What’s different, of course, is that Twitter isn’t just a protocol. It’s also a database. And that’s the old secret of Web 2.0, Data is the Intel Inside. That means that they can let go of controlling the interface. The more other people build on Twitter, the better their position becomes.

There’s a real lesson to Facebook here about giving other services (like Twitter) access to their social graph. They have the best one going, but because they try to keep users coming back to their interface, and even the applications built on their service have to live in Facebook, they end up as a ghetto rather than a true internet service. It’s the data, not the interface! Let other people use your data, build on it, and it will still belong to you. Hold it too tight, and they will compete with it.

Lots more to say, but the beach is calling on this sunny Saturday.