It comes as no surprise that the latest hack to come across the YDN radar is from one of our favorite hackers: Simon Willison. In idproxy.net: Use your Yahoo! account as an OpenID he describes what he's built. But if you've played around with BBAuth before, you can probably guess how it works already. :-)
Yup, idproxy.net serves as a bridge from BBAuth to OpenID. Not only that, it offers your own name in idproxy.net DNS space (I claimed Jeremy Zawodny.idproxy.net, for example) and an anti-phising monster.
Well done, Simon.