The online auctioneer decided toafter Microsoft made an "architectural change" to its online authentication service, an eBay representative told CNET News.com on Thursday.
The company's withdrawal of support and Microsoft's changes to the service were not unexpected developments and part of the planned evolution of Passport, Microsoft responded in a statement.
"Over the past couple of years, Microsoft learned a lot working with partners and customers, and shifted the focus of the (Passport) service to serve as a great single sign-on solution for consumers of MSN and Microsoft online services, as well as working with close partners where it made sense for both parties," the company said.
As reported by CNET News.com earlier this year, Microsoft has slowly been. The service acts as a central storage for personal information such as credit card numbers for use when shopping online. It also can act as a single sign-in and password for all a person's online accounts.
eBay's move comes as companies increasingly throw their weight behind federated identity standards, which allow each company to vouch for the identity of its users, rather than handing over control of the information to an outside company such as Microsoft.
Much like countries' passport systems, from which Microsoft's service takes its name, federated identity services allow users to be "citizens" of certain services and have those services vouch for their identity.
The federated service with the most support so far is, a group of technology providers and corporations that includes Fidelity and American Express. Founded by Sun Microsystems and others in 2001, the consortium now has more than 150 members. eBay is not a member of the Liberty Alliance.
eBay is the latest Microsoft partner to give the Passport system an exit visa. Online job site Monster.com dropped support for Microsoft's service on Oct. 22. A list of sites that had partnered with the software giant has been removed from the company's Web site, making it difficult to tally.
The risks for companies of relying on a single provider of authentication services were highlighted whenin Microsoft's Passport last year. The glitches did not just create doubt about the service's security but also .
eBay would not comment on the topic on Thursday or give any further details of its decision to ditch Passport.