Featured snippets in search
When a user asks a question in Google Search, we might show a search result in a special featured snippet block at the top of the search results page. This featured snippet block includes a summary of the answer, extracted from a webpage, plus a link to the page, the page title and URL. A featured snippet might look something like this on the page:
Where does the answer summary come from?
The summary is a snippet extracted programmatically from a webpage. What's different with a featured snippet is that it is enhanced to draw user attention on the results page. When we recognize that a query asks a question, we programmatically detect pages that answer the user's question, and display a top result as a featured snippet in the search results.
Like all search results, featured snippets reflect the views or opinion of the site from which we extract the snippet, not that of Google. We are always working to improve our ability to detect the most useful snippet, so the results you see may change over time. You can provide feedback on any Featured Snippet by clicking the "Give Feedback" link at the bottom of the box.
Opting out of featured snippets
You can opt out of featured snippets by preventing snippets on your page using the
<meta name="googlebot" content="nosnippet"> tag on your page. This will remove all snippets on your page, including those in regular search results.
How can I mark my page as a featured snippet?
You can't. Google programmatically determines that a page contains a likely answer to the user's question, and displays the result as a featured snippet.
Is this part of Knowledge Graph?
No, this is a normal search result, emphasized with special layout.