Re:One method to reliably track users... (Score 1)

Actually, while this is generally more accurate than other methods, it is far from accurate. I did an analysis for one of my customers and found that a single user/password was used on over 1200 computers during a single month.

This can happen as people share usernames (whose NYTimes login do YOU use?), frequent services like BugMeNot and people fail to logout when using a shared computer.