For want of a bit the user was lost: Cheap user modeling

The more a computer knows about a user, the better it can serve that user. But there are different styles, and even philosophies, of how to teach our computers about us-about our habits, interests, patterns, and preferences. "Cheap" user modeling, the subject of this essay, simply means ascertaining a few bits of information about each user, processing that information quickly, and providing the results to applications, all without intruding upon the user's consciousness. In short, there are techniques for personalization that can-and should-be built into today's systems. Like most journal papers, this is a description of an existing system: DOPPELGÄNGER. But it is also an exhortation for readers to incorporate the described techniques and philosophy into their own systems.