I read Maseko's post about Yahoo! OpenID and i realized i haven't activate my Yahoo! ID for OpenID, so i opened Yahoo's OpenID and activate my account. I tried to test it by giving comments to my friend's blog on Blogger and it seems that as Maseko stated, it's not working at all with the message : OpenID url is missing. It seems that both vendor uses different version of OpenID, but actually it supposed to be backward compatible, so why forcing to support the bleeding-edge technology when most site still uses the old version?
I guess Yahoo! OpenID is not usable for now until people or sites have moved to support OpenID 2.0. I still use my OpenID which i got from GetOpenID. It's working on Blogger and many other services.