microformats, rdf or microdata

Question

Is there any difference between using one of this technologies?

I\'m building now a site using HTML5, and I\'m having hard time to decide which one of them to use. I

Answer 1

Microdata is RDFa reborn tougher as seen from support to CURIEs being absent. schema.org addresses only the cross-cutting concern of search. Unless the content relates to domain specific aspects with semantic significance that merits it's own vocab or is simple enough to be covered by microdata, it might be just noise treated as spammy content by good search rank algorithm.
The fundamental difference from webmaster viewpoint is
schema.org + microdata is for content significant in the context of search
microformats is for the simplest content pieces that don't merit syntactic overheads
other vocabs + RDFa is for semantic content to be utilized through parsers with domain-specific significance outside searching context
and all 3 blend well in XHTML too, that's useful from analogy of serving weblog as feed for instance.
Key point here is there are better reasons to opt for microdata than being early bird at adopting it, while being respectful of earlier, more widely successfully deployed means.