Recently I picked apart what I thought was a pretty cool usage of microdata at Google—using it to specify recipes in their search results. But, of course, the black hat SEO community (black hat being how dishonest is pronounced in nerd) is completely gaming their results.
It seems the Google-included snippets of information are ridiculously easy to fake out. There are three primary pieces of info Google looks for: time of preparation, calories, and ingredients. Read this article to see how dishonest sites are artificially working their way higher in search engine results, and obscuring the content the Googler would actually be looking for.