Rich Snippets and Structured Data - RDFa
I've always been interested in optimizing this site for search engines and trying my best to make this site as efficient as possible. I recently stumbled across a blog post by the Google webmaster team that explained a little about rich snippets and how search results are returned when they have been marked up using structured HTML. I was pretty impressed with the way the results showed up.
Try some of these other queries and notice how the search results appear:
Both Google and Yahoo provide support for structured data, and I'm sure many more will follow soon (I don't think that Bing supports it just yet). Surprisingly, updating your site is really easy, and all you need is a basic knowledge of HTML.
You can mark up your structured HTML content in any of three formats:
- microdata
- microformats
- RDFa
For this site I chose to use RDFa, although you can use any of the three formats and it will be picked up by Google and Yahoo. Below is an example of some of my HTML that I have updated to include RDFa.
Here is an example of the HTML: 
Yahoo and Google have testing tools that you can use to check your results. I would say that I prefer the Yahoo version (called SearchMonkey) for now, merely because it offers a much better UI and a lot of work has been put into SearchMonkey. I would still recommend checking your pages in both tools for consistency. Google will probably offer better support for structured HTML soon.
These are the results for the above page on the SearchMonkey testing tool:
And Google rich snippets testing tool:
At the time of this article going live, this site was not included in the Yahoo search results. I have just re-submitted this site to the search engine crawlers again and I am hoping for it to be updated soon. However you can check that the structured HTML is being parsed by the search engines. Try this link (http://www.deanhume.com/Home/About) in the validate markup section.
Marking up your data for rich snippets won't affect your page's ranking in search results, and the search engines also don't guarantee that the markup will be included in search results. However, RDFa makes web browsers smarter by giving people more options when viewing a web page, such as adding you to their address book, adding an event to their calendar, getting directions to a place described by RDFa, or searching online bookstores for a book marked up using RDFa. I would definitely recommend using it!
Here are some useful links to get you started:
http://developer.search.yahoo.com/start
http://www.google.com/support/webmasters/bin/answer.py?answer=99170
http://knol.google.com/k/google-rich-snippets-tips-and-tricks#Basic_instructions