Just one of those things that I stumbled across through a dedicated Google search feed; Hieraki is an open source, Ruby-based (hence the reason you’ve probably never heard of it; many who try Ruby seem to rave about it but it never seems to gain traction versus its competitors) wiki-like system that structures pages by ‘Chapters’ and sub-sections to assist with collaborative book authoring. Someone has even tried building a ‘learning object repository’ named Noc on top of it. Not an endorsement, just a pointer to an interesting experiment. – SWL