sameAs.org is a great service on a number of different levels. It provides a much needed piece of Semantic Web infrastructure and it achieves that through a simple clean interface and API. You don’t even need to know anything about RDF to get value from the service. In short it’s one of those nice web services that do one thing and do it really well.

I use the service as a frequent example in my talks and training sessions on Linked Data. For example, while it’s useful to review techniques for linking together datasets, in practice you can achieve a lot by simply doing a series of look-ups against sameAs.org. I’ve had some happy experiences of discovering connections between datasets without having to do any manual linking.

More than a few times recently I’ve been thinking that it would be useful to repeat what Hugh Glaser and Ian Millard achieved with sameAs.org, but for a number of other common RDF predicates.

In my opinion there are a small number of general predicates that will act as the backbone for the web of data. At the head of the predicate long tail we’ll find properties like: owl:sameAs , but also useful properties like dc:subject , foaf:knows and foaf:primaryTopic .

The topic based predicates ( dc:subject , foaf:primaryTopic , foaf:topic , et al) are particularly useful for discovering documents and material that relate to a specific resource. An index of these would be extremely useful for inter-linking between content from different news and media organisations for example. I’d envisage that “topicOf.org” might index a range of different topic related predicates and expose some useful discovery tools, relations and equivalencies. Dan Brickley has a nice diagram that shows how these different predicates inter-relate.

“topicOf” is currently top of my list of these predicate based services. But the same approach would work in other contexts. For example a service that indexed foaf:knows would be useful for social networking applications. But I think that this area is already well-served by existing services already. But what about:

“reviewsOf.org” — find reviews about a specific resource. I believe Tom Heath has thought about doing something like with for Revyu

“depictionsOf.org” — find pictures of a specific resource ( foaf:depiction ), e.g. person, place or thing (and reliably, not like the Flickr Wrapper)

), e.g. person, place or thing (and reliably, not like the Flickr Wrapper) “madeBy.org”> — find documents, photos, or other resources that were made by a particular person ( dc:creator , foaf:maker )

I can think of all sorts of useful purposes for these services. I also think that they could offer additional ways of engaging with the broader developer community and getting them to buy into the Linked Data vision.

Anyone want to have a crack at implementing some of these?