Ask HN: Viable alternatives to passwords on the web?

I use probably 20+ web applications in the context of running my business and my personal life. For me, the current password based authentication/identification systems employed on the web are fundamentally broken. There are simply too many sites to keep track of, and since I access these services on multiple machines (home, work, iPad, iPod touch), its difficult to find a password keeper that works across these platforms.

It seems to me there is a fundamental plumbing opportunity on the interwebs with regard to providing a viable solution for identification and authentication. I know openid has taken a run at this, along with google and others, but none of them have really taken off.

Is anyone out there working on solving this problem? I realize its a big problem, but it seems also to be a big opportunity.