I haven’t seen an announcement about this, but try the following query on Yahoo Search: [searchmonkeyid:com.yahoo.rdf.rdfa] (link). It shows documents containing RDFa, with Digg at the top. Since this is a Searchmonkey ID, it’s also usable in Searchmonkey to actually extract the metadata and use it to customize search results.
Does your site use RDFa yet? -m
We’ll be making a formal announcement soon — we’re still tweaking how RDFa gets presented in the devtool. But yes, it’s real.