Google’s own webmasters help site recommends microformats and RDFa structured data to improve indexing and usefulness of the data. Review metadata appears to have full support, while people, product, and business data are in beta.
Longwell RDF Browser
Longwell mixes the flexibility of the RDF data model with the effectiveness of the faceted browsing UI paradigm and enables you to visualize and browse any arbitrarely complex RDF dataset, allowing you to build a user-friendly web site out of your data within minutes and without requiring any code at all.