A few new data storage technologies are currently getting attention, in particular graph databases such as AllegroGraph and Neo4j that allow to “structure on the fly” by using a multi-relational graph data model.
Check this slide share presentation: Graph Databases and the Future of Large-Scale Knowledge Management, by Marko Rodriguez from Los Alamos National Laboratory.
See also this short video on key technology dimensions and a longer talk by
Franz' Jans Aasman demonstrating some capabilities of his AllegroGraph RDF graph database:
NYCSW GeoSpatial, Temporal Reasoning with AllegroGraph from Morton Swimmer on Vimeo.
More on Neo4j:
Neo4j -- graph databases presentation