It fills an important niche in the SSO space, namely the 'Monthly SSO system claiming to be simpler than SAML' niche.
The idea of sharing your Identity Provider account password with random Service Providers seems attractive. After all, if I'm presenting it to every site I interact with I'm less likely to forget it. As they say in the Guiness ads, "Brilliant!".
The following sentence particularly caught my attention.
The Liberty Alliance has churned out a number of PDFs but that seems to be the extent so far of their effort.
I don't know why people are constantly scoping the Liberty Alliance down to the publication of just PDF documents - we are far more than just that. It seems that just because the best known examples of our published material are in PDF, then somehow we get typed as only publishing in PDF.
Fundamentally, the Liberty Alliance defines a marketing framework, a platform on which can be built systems capable of publishing in a variety of formats appropriate to different marketing applications. Any particular publishing run is able to use the Liberty framework in a manner that suits the sort of marketing campaign being targetted. Examples of particular file formats supported by the Liberty framework include Powerpoint, HTML, JPEG, Flash etc and of course, yes, PDF.
There are lots of publishing frameworks that support one or two of the above formats, LAP is, AFAIK, unique in its "publishing format breadth".
Update: Conor reminds me that Liberty has also published in plaintext. I also forgot WML. This just reinforces my point about the flexibility of the Liberty publishing engine.
Conor also implies that, in my eagerness to deride, I missed the point. Ah my constantly green-clad Irish friend, I knew full well that others would make the 'billion Liberty-enabled identities' & 'countless deployments' argument (as well as dig deeper than I did in an actual security & privacy assessment of the proposed SSO solution).