Open ID
Some thoughts on OpenID and the Identity Systems of Yahoo, Google & MSN by Emre Sokullu and Richard MacManus at Read/Write Web.
The big idea in OpenID is providing a decentralized single sign-on platform.
The reason they do this is that signing up is actually a big barrier to entry for users of web apps. Users feel more comfortable when they don’t have to sign up to use an app - it’s much easier to give it a try and it’s less time-consuming to start using it. That’s why most web sites today try to keep sign up process as short as possible.
Even though the system is completely decentralized, OpenID still raises privacy concerns. Some people don’t want to have a central place that binds all their accounts. Another criticism is whether the system is fully de-centralized? As always, this space is vulnerable to one provider eventually dominating it. So any disequilibria may put the neutrality of the system under question.