Structured data makes the Web go around. Search engines love it when webmasters mark up page content. Google’s rich snippets, for instance, leverages sites’ use of microdata (preferred format), or RDFa or microformats: It makes it possible to highlight in a few lines specific types of content in search results, to give users some insight about what’s on the page and its relationship to their queries – prep time for a recipe, for instance.

Plenty of web sites generated from structured data haven’t added HTML markup to their pages, though, so they aren’t getting the benefits that come with search engines understanding the information on those web pages.

Maybe that will change, now that Google has introduced Data Highlighter, an easy way to tell its search engine about the structured data behind their web pages. A video posted by Google product management director Jack Menzel gives the snapshot: “Data Highlighter is a point- and-click tool that allows any webmaster to show Google the patterns of structured data on their pages without modifying the pages themselves,” he says.

All they need to do to get started is to put in the URL of the page with structured data, and highlight important fields for labeling from a drop-down list. Once that’s complete for the page, the tool will show webmasters similar pages with similar data already highlighted, which webmasters can review and correct. (Webmasters have to specify page sets, each one a collection of pages on their sites that display the data consistently and are organized so that URLs follow a simple pattern.) Clicking Publish gets the patterns applied across the site.

A few caveats: To be clear, the data that Data Highlighter extracts is available only to Google, so it’s not useful in other search engines. Also, Data Highlighter can be applied only to pages that Google has recently crawled. And each time it crawls the page subsequently, it will extract data for use by rich snippets, so significant changes to how information is displayed or to the site’s URLs requires re-teaching Data Highlighter about the new site structure.

And, while Google supports rich snippets for reviews, people, products, recipes, businesses and organizations, music, and events,  Data Highlighter so far has only events in its quiver. If you use Data Highlighter to tag the name, location, date, and so on for the events on a site, Google says, the next time the search engine crawls your site, the event data will be available for rich snippets on a Google search results page – showing tour dates, for instance.

The Google Knowledge Graph can display data extracted with Data Highlighter’s help like this, too:

How to decide if Data Highlighter is the right approach for you? Here’s Google’s advice: Use it if:

  • Your site displays the types of data supported by Data Highlighter.
  • You’re considering structured data and rich snippets for your site, but you are not yet ready to commit resources to updating HTML markup.
  • You prefer to point and click on web pages instead of writing HTML markup.
  • You can’t change the HTML markup on a site, or you can’t consistently mark up data items.