This is being adopted by many online service providers...In few years, it will be enough to remember only one ID and can be used across all providers...
More info in the below link...
http://openid.net/
Also, few days back (last week) Blogger also started to support OpenID. So, you need not have a blogger account to add comments etc in blogger or any other domain.
Some of the openID providers as of now (This may/will increase in future as many vendors are supporting openID)
AOL
LIVEJOURNAL
ORANGE
etc.
For more generic information visit the wiki page below.
http://en.wikipedia.org/wiki/OpenID
Summary
QUOTE
OpenID is a decentralized single sign-on system. Using OpenID-enabled sites, web users do not need to remember traditional authentication tokens such as username and password. Instead, they only need to be previously registered on a website with an OpenID "identity provider" (IdP). Since OpenID is decentralized, any website can employ OpenID software as a way for users to sign in; OpenID solves the problem without relying on any centralized website to confirm digital identity.
OpenID is increasingly gaining adoption among large sites, with organizations like AOL and Orange acting as a provider. In addition, integrated OpenID support has been made a high priority in Firefox 3 and OpenID can be used with Windows CardSpace, which is part of .NET Framework version 3.0 (the .NET Framework version 3.0 comes with Windows Vista by default and can be downloaded for Windows XP).
OpenID is increasingly gaining adoption among large sites, with organizations like AOL and Orange acting as a provider. In addition, integrated OpenID support has been made a high priority in Firefox 3 and OpenID can be used with Windows CardSpace, which is part of .NET Framework version 3.0 (the .NET Framework version 3.0 comes with Windows Vista by default and can be downloaded for Windows XP).
