The Liberty Alliance Project is a consortium that develops specifications for services related to online identity. Internet2 has contributed by invitation to a number of their specifications dating back several years.

Of late, these specs have been divided into three broad groupings:

Liberty ID-FF: Identity Federation Framework
Liberty ID-WSF: Identity Web Services Framework
Liberty ID-SIS: Identity Services Interface Specifications

The first of these, Liberty ID-FF (through version 1.2), was a forerunner to the SAML 2.0 specification. SAML 2.0 is now an OASIS standard and is the basis of the next major version of Shibboleth. All of the functionality in ID-FF has been incorporated, usually in more coherent fashion, into SAML 2.0, and there are no plans by the Shibboleth Project to support any of the historical Liberty ID-FF specifications. Consider ID-FF a legacy platform.

The Liberty ID-SIS specifications are essentially applications, high-level web service interfaces that support particular use cases like data/profile, geolocation, contact book, and presence services. These may be of interest to Shibboleth deployers in the future, but are essentially the top of the stack and may be useful as examples of what ID-WSF can do as much as anything else.

Liberty ID-WSF is the focus of some of the future work that the Shibboleth development community might engage in.  There are no promises other than to say that as a standards-based software project, it makes sense to evaluate whether these specifications provide viable solutions to some of the use cases that go beyond current work.

We suggest interested parties with their own extensions and adaptations of Shibboleth or related code seriously evaluate their use cases against these specifications before pursuing overlapping proprietary solutions.

Some hopefully helpful material:

LibertyWSFIntro
LibertyWSFRoadmap