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Schema.org is a collaboration, in the spirit of sitemaps.org, between Bing, Google, Yahoo! and Yandex to make it easier for webmasters to provide us with data so that we may better direct users to their sites.
Going forward, schema.org is the microdata format that will be supported by the big three search engines, but you can keep what you've already done in the other formats mentioned....
but there doesn't seem to be a way to mark key index pages for publishers