I wrote before that Riak links is a very web-like and interesting feature (nb truth being told this is not the only Riak exclusive feature). Michael Hausenblas has tried to use Riak links for storing an RDF graph in Riak
The main issue then was how to map the RDF graph into Riak buckets, objects and keys. Here is what I came up so far — I use a RDF resource-level approach with a special object key that I called:id, which is the RDF resource URI or the bNode. Further, in order to maintain the graph provenance, I store the original RDF document URI in the metadata of the Riak bucket. Each RDF resource is mapped into a Riak object; for each literal RDF object value the literal value is stored directly via an Riak object-key, for each resource object (URI ref or bNode), I use a Link header.
Due to their high connectivity graph databases are difficult to scale and this approach could be an interesting approach.
Original title and link: Riak: Storing an RDF Graph (NoSQL databases © myNoSQL)