The Yahoo! OpenID (beta) which was announced earlier this month has just been launched. You can try it out right away. This is expected to move the OpenID movement ahead considerably. All 250 million members of Yahoo are now able to log in to any website, not just Yahoo, that supports OpenID 2.0.
At this moment you can find very limited list at Yahoo which I hope will be expanded soon.
I have been testing OpenID login with WordPress.com who also offers OpenID. Right now it seems WordPress has a more attractive offer than Yahoo. At Yahoo my OpenID URL is:
While at WordPress.com it is:
I think I prefer the WordPress version…
UPDATE: It is possible to change your Yahoo identifier URL into something more easy to remember. I overlooked this possibility when I checked the service yesterday. This means that my Yahoo identifier is now https://me.yahoo.com/openidboris. I still think http://bomega.wordpress.com is easier to remember. Thank you Adam for pointing this out to me.