Structured Snippets is a new feature integrated into search results that incorporates facts into individual result snippets. Interesting and relevant facts are extracted from the content page and displayed on search results. These can be important dates or events, technical specifications and features, price etc.
For example, if you search for a comic icon, say superman, you can see some extra information next to its Wikipedia entry such as creator, first appearance, origin etc.
This feature isn't limited to Wikipedia entries. When you search for a gadget, you will see some of its features displayed right there on search results.
Since this feature isn't exclusive to a select few sites, we can hope to see more of these snippets soon. Here's Google's explanation for the new 'richy' rich snippets;
Structured Snippets is the latest collaboration between Google Research and the Web Search team employing that data to seamlessly provide the most relevant information to the user. We use machine learning techniques to distinguish data tables on the Web from uninteresting tables, e.g., tables used for formatting web pages. We also have additional algorithms to determine quality and relevance that we use to display up to four highly ranked facts from those data tables.
A good question that can be asked is, how will Google asses the quality of facts surfaced by theses structured snippets? Google says that will wary according to page content, but that just means another black box which webmasters will speculate about, but will never really understand.
Let's hope Google has done better homework on this one compared to what it did with sitelinks. We'll keep you updated about these structured snippets so that you will be able to add relevant ones to your site as well to improve your click-through rate. Stay tuned :)