Federated wiki is a cool idea and all, but I don't want to have to build my own wiki of everything, or decide what concepts should be included in my own wiki. The whole strength of wiki to me is that it massively multiplayer user curated content, where the whole state is determined by everyone working together. I don't know what happens to that curation if there's no authoritative source -- it seems like federated wiki isn't really wiki at all, and is something else entirely.