There's an old saying that, on the Internet, no one can tell you're a dog. It turns out that that's probably not true. In fact, anonymity is going to be getting hard with this kind of analysis.

...differences remain in the way that people tap out their electronic secrets. Internet users have characteristic patterns of how they time their keystrokes, browse Web sites, and write messages for posting on online bulletin boards. Scientists are learning to use these typeprints, clickprints, and writeprints, respectively, as digital forms of fingerprints.

While the aims of this research are to strengthen password security, reduce online fraud, identify online pornographers, and catch terrorists, the technology is raising some troubling possibilities. "It's a bit scary," says Jaideep Srivastava, a Web researcher at the University of Minnesota in Minneapolis. "The privacy implications are huge."

[Via Geek Press]

I don't buy the summary.

My typing varies from first word to last, and there is no way in hell that there is a logical progression or reduction based on my personality.

Also it seems that the typing thing can only apply to chats, and not posting or commenting or any of the other much more manageable methods of communication.

Well, if it's about chats, they can identify me without doubt:

Keystrokes: 0

It is because of tracking software like this that I randomly visit pornsites in the middle of my work.