It is a truism that as the Web grows in size and scope, it becomes harder to find what we want, to identify like-minded people and communities, to find the best ads to offer, and to have applications work together smoothly. Services don't interoperate; queries yield long lists of results, most of which seem to miss the point. If the Web were a person, we would expect richer and more successful interactions with it - interactions that were, quite literally, more meaningful. That's because in human discourse, it is shared meaning that gives us real communication. Yet with the current Web, meaning cannot be found.Much recent work has aspired to change this, both for human-machine interchange and machine-machine synchronization. Certainly the "...