While Sig.ma is by no mean the first data aggregator for the Semantic Web, its contribution is to show that the sum is really bigger than the single parts and exciting possibilities lie in a holistic approach for automatic semistructured data discovery and consolidation.
In Sig.ma, elements such as large scale semantic web indexing, logic reasoning, data aggregation heuristics, pragmatic ontology alignments and, last but not least, user interaction and refinement, all play together to provide entity descriptions which become live, embeddable data mash ups.