I just discovered Ward Cunningham's Smallest Federated Wiki. It's amazing that the man that first innovated the revolution in internet collaboration and sharing seems poised to do so again. Anyone who knows me can tell you how much I value the idea of federation on the web, whether it be social networks, chat, mail, version control, or wikis. Federation is, in my mind, without a doubt, both the past and the future of the web. There are challenges, to be sure: federated search exists, for example, but is extremely difficult to do well. Messaging of various kinds (email, IRC, instant messaging) is a natural fit. Distributed, federated version control is not only possible, it dominates on the web. Social networks are really a form of messaging, so they should be federated, even though the main networks are not.
Wikis are a less obvious application of federation. I've long believed that a federated wiki is really a way to expose the basic functionality of distributed version control through a browser. I even implemented a federated (distributed) wiki based on Mercurial a few years ago. But watching Ward Cunningham's videos makes me realize that there is a whole lot more we can do with federated sharing on the web. It reminds me how lucky we are to have folks like Ward Cunningham leading the charge on such efforts.