- HTML is often referred to as the foundation of the web. It's the core language of every website and it has a rich set of tags for describing the structure of webpages. However, by design HTML has a limited set of tags that, for the most part, are restricted to defining document structure and specific UI elements. This means that, while there are tags that identify common page elements like headers, footers, and articles, there aren't really any tags that define common content types like people, products, and events.
Now, this is by design as HTML's small element set actually makes the language easier to learn, simpler to parse, and easy to implement across multiple user agents. It does, however, make it a little bit more difficult for search engines and other user agents to correctly identify and understand your site's content. This is where structured data comes in. Structured data is a loose term that encompasses a number of vocabularies and syntaxes that can be combined with HTML to provide a richer level of detail when describing your content.
This will help search engines more accurately index your site, improve search results, and add an additional level of semantics to your content that user agents can take advantage of. Take this listing of a person's contact information. Although it might be easy enough for us to scan the page and find the data that we need, a search engine wouldn't automatically understand how all of this information relates to each other. By supplying it with structured data, we can dramatically improve the semantics of the content and make the information more meaningful to machines that understand this.
You can see this structured data at work whenever you do a search through an engine like Google or Bing. Now, let's say I do a search for a recipe for apple pie, which happens to be my favorite dessert. Notice how some of the results show a little bit more information than others. Some of them have ratings attached to them, photos attached to them, preparation time, while others don't. Now, this is largely the result of structured data that's been added to those sites. It creates better search results, and increases the likelihood that the searcher is gonna click through to your site.
This doesn't mean that you need to use structured data everywhere in your markup. It's actually best suited for highlighting specific pieces of information, usually the subject or the focus of the page, or an important piece of content that needs to be indexed accurately. By taking advantage of structured data, you can create sites that are more meaningful and that have more relevance to search engines and other user agents.
- Choosing a syntax
- Learning microformats
- Structuring contact data
- Adding contact names, titles, photos, and addresses
- Learning RDFa
- Structuring event data
- Providing event dates
- Adding an event URL
- Learning microdata
- Structuring products
- Setting product pricing
- Adding individual product reviews
- Learning JSON-LD
- Creating a knowledge graph