Issues in Using OpenID
Like any Internet service that can associate personal information, OpenID have issues, concerns and benefits. The only advantage that I can see in using an OpenID login system is to reduce the creation or maintenance of usernames, passwords or online accounts.
The concerns pertaining to OpenID all about phishing attacks, trust and privacy. And I wonder, what if a hacked Gmail, Yahoo, Hotmail or Windows Live ID is being used by hackers to login to websites using the OpenID login system as "you"? There is no way for OpenID providers and OpenID itself to find out whether the account is one of the hacked accounts because it will only provide an answer to the OpenID authentication system, whether the account really exists in their database. And when it successfully checked that the account exists, the information is presented to the hacker which has the option to edit what information is to be displayed e.g. your first and last names, and e-mail address.
Allowing a site or service to share your login credentials or even an email address is a big privacy concern already to many privacy conscious users, so only use the service of OpenID when you trust that your account is not hacked or being spied on.
Image credit: http://commons.wikimedia.org/wiki/File:Openid.svg By User:ZyMOS [Public domain], via Wikimedia Commons. Screenshot taken by the author courtesy of http://hphosts.blogspot.com/