cc Learn
One of the most compelling applications of open content is in the educational sphere. After all, it's crazy for teachers to keep on creating the same content again and again: the whole idea of knowledge is to build on what has been learned. So it's good to see the Creative Commons setting up a new arm aimed specifically at promoting the re-use of materials here. It's called ccLearn: at the moment, there's not much to see there apart from the Open Education Search project, but I'm sure that things will grow quickly - the logic is compelling.