A class of services that complements and builds upon the CC infrastructure includes assurance, provenance, registration, and warranty. Numly and RegisteredCommons are two currently pioneering organizations in this space.
Chris Matthieu of Numly started a descrption and comparison table for the space on the CC wiki. People from RegisteredCommons have added. Other experts or those merely interested are encouraged to contribute as well.
Both projects have or are working on search, Firefox integration, WordPress integration … the whole Web 2.0 bag of tricks. “Copyright 2.0” is what Chris Matthieu calls it.
iCommons did a Q&A with RegisteredCommons last month.