Ma.gnolia.com has added OpenID support.
Their single-line description of what OpenID provides is going to scare (or a least confuse) some.Most user already sign-in to different sites with the same password. Is 'safely' sufficient distinction?
The 'Get an OpenID' link goes to MyOpenID, the URL parametrized by an affiliate ID. Playing around with different values for this gives an interesting sense of who is using OpenID. Such an open and accessible listing of SSO partners creates for me a uneasy feeling though.