A nice concept, if only it didn't require you to turn off some of your security settings in order for it to work.
The idea of being able to use a common login module to login to multiple systems is quite a nice one however the way that this has been implemented is slightly flawed.
In order to test this one I actually tried three different OpenId systems - one that uses a graphical system to generate a dynamic password that is different each time you log in, one using a conventional login, and one that you can install on your own site to give you your very own open Id system. None of the three worked successfully when I tested them with the latest version of Opera until I told the browser to accept all cookies. While the latter two allowed you to login to the login system it couldn't actually then connect into the system you were actually trying to access with third party cookies blocked. The graphical dynamic password system couldn't even get as far as requesting a password in this situation and was extremely slow loading (as in go get yourself a cuppa while you're waiting) even when it did work.
The other annoying thing is the difficulty of getting rid of the OpenIds when you don't want them any more. The only one of those that I tested that had a clean removal system was the one you install for yourself where all you need to do to remove it is to delete the files you added to create the system in the first place. The graphical system also has a delete account process that can remove the unwanted account provided that you can find a way to log into it in order to request the delete. The other system had no delete option at all, not even a form to request deletion and so the best that can be done in that one is to remove all your personal information and insert a dummy email address and junk password and hope that the owners get enough bounce emails to delete it for you.
If you do decide to use OpenId and you have your own web site then I suggest the self hosted version is the neatest of the alternatives.