This site provides a collection of schemas, i.e., html tags, that webmasters can use to markup their pages in ways recognized by major search providers. Search engines including Bing, Google, Yahoo! and Yandex rely on this markup to improve the display of search results, making it easier for people to find the right web pages.
It sounds wonderful, but does the search spider ignore the extra attributes and elements? Is it just too clever and ignores it? May it also be that it lowers your visibility because of such alteration?