Finally, thanks to a discussion with Eric Neumann a few weeks ago, I'm beginning to understand what Linked Data is all about. First a caveat -- although I credit Eric for helping me see how linked data fits into what I'm doing, the following interpretation is strictly my own as are errors of omission, commission or orthogonality, although I think my view is supported by the Design Issues document.
The short story is that linked data provides stable identifiers for stuff (a more abstract form of things). These stable identifiers then allow you to say things about this (particular) stuff without necessarily making a strong ontological commitment.
I like this. It provides for interoperability and integration. It does not provide any inference guarantees which is fine by be, and something that I have been advocating for a while. The Linked data site also has links to a number of datasets which publish stable identifiers for useful stuff. The site also gives examples of how to publish your own data.
Hopefully data.gov will provide its data in this form in the near future.