It seems that Bitcoin is only designed to eliminate the need for centralized issuer and central authority, but not anonymity, which is a common misconception among internet users as according to one of its developers (Jeff Garzik), transaction is recorded in public log and although the identity of the parties involved can’t be directly identified, the transaction can be easily traced and linked to other accounts through data mining and statistical analysis.
So it is harder to stay anonymous in transactions that involve large currency value.
Bitcoin is not anonymous
The Battle Is On – Silk Road vs Government, and Bitcoin Anonymity
OpenID is a standard that allows users to be authenticated in a decentralized manner. OpenID enables user to be identified across the internet using a single unified OpenID identifier (or account).
However some websites (particularly blog and forums) insist users to login in order to leave a short comment or remarks which sometimes is not convenient for some users that value anonymity.
The OpenID Anonymity service is an OpenID provider that helps you get around website or application that requires OpenID login. To use OpenID Anonymity service, the user only need to key in its URL Identifier – http://openid.anonymity.com/some_random_id and the user will be automatically authenticated, without the need to log-in or to enter password, which is very convenient if one needs to be anonymous.
p/s: Additionally here’s a collection of Public Domain OpenID (tangofied) icons, created by Jakub Szypulka