Computers hate people, and with good reason. I'd hate me, too, if I were a computer.

People -- human beings, all of us, to a one -- are messy, ugly, disastrously disorganized creations. We don't make sense -- don't fit into comfortable categories, don't follow reliable rules, don't have any sort of structure to how we function, communicate or express ourselves.

Computers hate that. They can't cope with it. The idea of trying to catalog anything but the simplest metadata about people in a format that's easily parsed by a computer is ridiculous. It's hard enough getting a few pieces of information specifically designed for machines right, much less the swampy mess of human-to-human interaction.

Not that people haven't tried, of course. Tried and failed, again and again and again.

The history of "social software" -- an important part of this nutritious Web 2.0 start-up -- is composed almost entirely of spectacular failures to capture all but the most rudimentary relationships between people. Most are divided into two camps: laughably simple and laughably complicated.

Too-simple social software has been the more successful to date, because it's actually usable. While too-complicated software attempts to stuff a doughy blob of human interaction into the square hole of the third-normalized form -- "This person is a friend," "This person is a friend if he's buying," "This person isn't a friend, but will get all pissy if don't add him," "This person is an asshole" -- too-simple software punts on the problem of actually reflecting reality and divides the world (usually) into four giant camps: me, my family, my friends and everybody else.

To which a functioning human being -- loose in the real world -- can only say: Ha.

Which family? Nuclear? Biological? By law? Former? Which friends? Work? School? Neighborhood? Electronic? Various combinations of all of them? Each of these groups can and do have competing agendas and competing reasons to access information, and each must be handled differently. Anybody who thinks that "the family" is a single, cohesive unit has never lived through a Thanksgiving dinner.

Flickr and Vox and LiveJournal and Upcoming and all the rest of the simple-social software products are produced by very smart (and attractive!) people, and they know that their division of relationships into four boxes is unrealistic, but they've apparently given up on doing anything about it. But the answer is staring them right in the face.

Flickr, for instance, pioneered the move away from insanely complicated and incomplete organization hierarchies by using tagging, and letting the user decide what their organizational structure would be. I was dubious of tags a couple of years ago, for all the boring semantic reasons. But they've proven to work spectacularly well: instead of trying to capture and catalog the whole of creation, simply give people the tools they need to do it themselves, for themselves. Don't try to get the computer to understand the world, because it never will. Let the human's do the work of cognition and evaluation and just return the damned database records. Easy, simple and "good enough" in exactly the right way.

So why not apply the same approach to social permissioning? Let the users decide. Don't make them force their lives into arbitrary categories -- give them the tools they can use to build their own. Not "Family," but "My parents" and "My sister's family" and "My wife's crazy grandmother who gets jealous if she sees too many pictures of my kids with my family" and God knows what else. Oh, sure, use the four classic groups -- "Me," "Family," "Friends" and "World" -- as defaults and that will satisfy some significant portion of users. But don't limit everybody to that overly-hierarchical, overly-simplistic worldview. It doesn't work.

Human beings (and their relationships) are complicated, messy, ugly things. A smart computer would want nothing to do with them. But if social software is going to insist on wading into the muck, it's going to have to be willing to get messy, too.

Because otherwise the hate is going to flow both ways.