IBM used name tags equipped with radio frequency identification (RDIF) technology to track attendees of its Information on Demand conference in Las Vegas.

The company said it would remove the RFID chips from the name tags of people who didn't want them, but only 2 percent of the 6,500 attendees took it up on the offer, said Mary Ann Alberry, IBM's conference manager.

Attendee Bill Miller, an independent DB2 consultant working in Frankfurt, said he has "a somewhat negative opinion" of the tags because of RFID's potential for abuse.

Alberry said data collected from the tags could help IBM plan future conferences. For example, organisers could use it to create sessions based on attendee interests.