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.
I get a bunch of emails like this: We have recently received a notification from Google stating that our website has unnatural links pointing towards it. This has affected our rankings on Google and as a result, we’re trying to clear things up. Our website URL is www.builddirect.com. We noticed the following links are pointing […] » about 300 words