How do we find out that two bits of RDF describe the same resource? The usual approaches are either to agree on a common URI scheme (which is often impractical), or to use inverse functional properties and smushing (which is complex and brittle). Phil Dawes describes another approach:
The recent folksonomy phenomenon has shown us that it is possible for serendipidous linking to happen on a large scale. This is achieved by leveraging existing real-world semantic grounding in shared (and well known) terms, and then requiring that clients do their own work in using context to disambiguate terms. […] Instead of having lots of unconnected data that must be painstakingly merged centrally [which incidently is what’s going on now when we attempt to convert other data to RDF, and when we create owl mapping statements], you have the opposite problem: lots of over-linked data which the consumer must disambiguate (and choose which links to follow) based on an operating context.
Phil goes on to say that this disambiguation is much simpler than the task of joining things together. Ask for the company tagged “apple” or the fruit tagged “apple”.
I’m not sure what to think about this. The idea is “un-semwebby”. When I think about a “working” semantic web, I envision an entirely automated system. Got a new bit of RDF? Just push it into the pipe, and the system will digest it and index it and hash it and p2p it and sparql it and everybody can use it. But maybe another level of human decision-making and intervention is necessary. (Just as a stop-gap?)
By adding tags, you could publish your RDF into a certain “pool” of information, which is watched by those parties that are interested in the tag. The great thing about tags is that they are a social solution to a technical problem. Making web resources findable seems like a technical issue, but assigning and discovering tags is a purely social problem.
Maybe it’s just me, but the idea of a del.icio.us where you tag RDF files or RDF services or RDF resoures, with an API, sounds like an awfully sweet idea.