NYCFacets: Metadata, Extrametadata and Crowdknowing

This document discusses using open data and crowdsourcing to create collective knowledge systems. It proposes extracting metadata and deriving "extrametadata" from open government data through algorithms and crowd contributions. This enriched metadata would then be semantically linked and made available through a federated search system. Key elements include extracting detailed metadata about datasets, characterizing datasets using metrics like freshness and social scores, enabling microcontributions from users, and performing federated queries across the metadata and source data.