Rich snippets appearing in Google are now supported in three versions or languages; formerly, Google offered microformats and RDFa support, and has now added support for microdata, which is a part of the HTML5 specification.
In May of last year, Google first announced rich snippets on their Custom Search blog, with a lot of restrictions:
At this time, Rich Snippets attribute information for Custom Search is only returned in XML (via <PageMap> tags), so you can use your own customized presentation controls. We’re looking to make this easier for you in the future. Indexing of the rich snippets information can have unspecified latency, as some pages are indexed and refreshed more frequently than others, and PageMap attributes may not be indexed from all webpages… If you are getting results back via XML, then the custom attributes are returned in the results within the PageMap tag, as shown below. You can parse the DataObjects within the PageMap tag and provide customized presentation of the relevant attributes.
This meant that XHTML verification was highly important.
Now more options are open. From the Google Webmaster Central Blog:
Today, we’re happy to announce support for microdata for use in rich snippets… By using microdata markup in your web pages, you can specify reviews, people profiles, or events information on your web pages that Google may use to improve the presentation of your pages in Google search results.
Here’s an example:
The blog goes on to exoll the simplictity of the system, and to warn that rich snippets are not guaranteed, but requests for inclusion can be submitted:
Microdata has the nice property of balancing richness with simplicity. As you can see, it’s easy to add markup to your pages using a few HTML attributes like itemscope (to define a new item), itemtype (to specify the type of item being described), and itemprop (to specify a property of that item). Once you’ve added markup to a page, you can test it using the rich snippets testing tool to make sure that Google can parse the data on your page.
It is still a good idea to get an XHTML validation service to check your site and ensure that you get all the perks you can!
Tags: microdata, rich snippets, XHTML validation