It’s been a very busy week for users of microformats. We made our announcement of the important new value-class-pattern over the weekend. That’s the culmination of a huge amount of brainstorming and community effort, and offers great improvements to using microformats accessibly and in international contexts.

Then since Tuesday, things have gone stratospheric. Google announced support for microformats right in their search engine, through a new ‘Rich Snippets’ feature, exposing hReview and hCard content within search results for many millions of users.

Rich Snippets give users convenient summary information about their search results at a glance. We are currently supporting data about reviews and people. When searching for a product or service, users can easily see reviews and ratings, and when searching for a person, they’ll get help distinguishing between people with the same name. It’s a simple change to the display of search results, yet our experiments have shown that users find the new data valuable—if they see useful and relevant information from the page, they are more likely to click through.

— Kavi Goel, Ramanathan V. Guha, and Othar Hansson in the Google Webmaster blog.

It’s a big day. hCards and hReviews are already published in huge quantities all over the web (see lists of sites that publish hCard and hReview), but this is the biggest user-base so far to benefit from the consumption of microformats in an application.

It’s again wonderful to see microformats embraced as a way to enhance user experience and to see it shipped to such a large audience, so congratulations to Kavi, Ramanathan, Othar and their Google team on the launch.

Initially Rich Snippets are only displayed for a handful of domains, so if you’re an hReview or hCard publisher, add yourself to Google’s waiting list now!. And if not already listed, update our examples in-the-wild wiki pages too (hCard, hReview).

If you’re a developer new to microformats we highly recommend you refer to the large set of code examples on our wiki, which will help you get started: hCard examples, hReview examples. There’s also full hCard and hReview documentation.

Finally, if you need help checking your code, check the debugging tools wiki page for validators, linters and debuggers.

It’s fantastic to see microformats applications hit such a large search audience. From the earliest experimental index at Technorati, to Yahoo putting microformats into mainstream search with SearchMonkey in March of last year; we’ve come a long, long way, and it’s looking great. With Google adding support for two of the major microformats, it really underlines structured data as a concrete foundation of the open web, and modern web development in general.

And yet more! An immediate benefit to everyone from the Rich Snippets release: Yelp have added hReview and hCards to all of their listings. You never need copy and paste a restaurant address by hand again!