OpenID?

identi.ca allows OpenID users to post small text notices and subscribe to the notices of their friends..

Jyte allows OpenID users to make claims and have the community vote on them.

Pibb allows OpenID users to IM, chat, email, and post bulletins.

Plaxo allows OpenID users to keep track of what their friends, family, and business contacts are doing.

Zooomr allows OpenID users to share photos and images with other users, and to tag, comment, track, and organize images.

MyChores helps OpenID users track their daily tasks and even track their progress with statistics.

Wikispaces allows OpenID users to create simple web pages that groups, friends, & families can edit together.

DziAnt.com allows OpenID users to easily add travel and contact information to their iPods.

Twitterfeed allows its OpenID users to easily send and read other users' updates.

myExperiment makes it really easy for OpenID users to build scientific communities.

LOL allows OpenID users to read, post, and vote on jokes

Blogger allows OpenID users to create their own blog and control who can read and comment

IconBuffet allows members to purchase stock icons for web design.

Velog allows OpenID users to log their bicycle rides and connect with others in the cycling community.

CNN Politics allows OpenID users to enter the Political Market to predict the future of the 2008 presidential race.

Mixx allows you to register and login using an OpenID to get your “mix” of the web.

Microsoft HealthVault allows myOpenID users to easily login to their HealthVault account.