Wearable Tracking Tags Test Privacy Boundaries at the U. of Washington

It's 2 a.m. Do you know where Evan Welbourne is?

If the University of Washington graduate student is burning the midnight oil at the computer-science building on the campus here, finding him is as easy as logging on to a Web page. Whether he is walking down the hallway or lingering outside a professor's office, an invisible monitoring network tracks his location and reports back to a database.

Mr. Welbourne doesn't mind. He has agreed to take part in a university experiment