Consider government data. The goal and focus of open government data (OGD) is to facilitate the sharing of machine-readable datasets covering government activity. This is an international effort with the four largest sites being www.data.gov (U.S.), www.data.gov.uk (UK), www.data.gouv.fr (France), and www.data.gov.sg (Singapore.) A list of datasets and catalogs can be found at http://logd.tw.rpi.edu/demo/international_dataset_catalog_search. Governments prefer releasing data through OGD portals because it is less costly than publishing reports. These sets are often heterogeneous structures and formats (not 5-Star data).
The web is a distributed and interconnected highway of information. When others (other web services) want to consume your data, the more references it has, the more integration points it has. In interlinking published data on the Web, you’re enabling reuse of your information.