From a Seattle Times article on the Feds' interest in Passport as an online identity card:
“Microsoft says it has 200 million people registered to use Passport, most of whom signed up because Microsoft told them it was needed to use other Microsoft services, such as its free Hotmail e-mail service or Windows XP operating system. According to Gartner, a research company based in Stamford, Conn., only 2 percent signed up because of the service's stated purpose: to avoid having to use multiple identifications and passwords at different Web sites. “