Which microdata is the best for a Q&A page or for a list of links to Q&A pages. When searching "yahoo answers cat" via Google it displays the result from Yahoo in a very nice way. It displays a list of related question with the number of answers.
What microdata/microformat should be used on Q&A pages like Yahoo Answers or StackExchange to have similar results in Google?
The rich snippets that you are talking about are pulled from the Google knowledge graph which allows certain rich content to be appended to the top search results where the Google algorithms deem it most appropriate. Google uses machine learning techniques to distinguish data from the structured layout of your page. As a webmaster you can use microdata to make this easier for Google and other search engines to access the information however there is no real way to force this information to be shown and only if the Google algorithms detect that the search someone is trying to perform would be improved by appending the rich snippets to the search results will they do it. As more websites adopt microdata and the standards become more accepted by the industry at large you will start to see it happening more.
References
https://searchenginewatch.com/sew/news/2372043/googles-new-structured-snippets-pull-facts-into-a-pages-search-results
https://en.wikipedia.org/wiki/Knowledge_Graph
http://schema.org/docs/gs.html
