Schema & Microdata: An Overview


The first ever website was published in August of 1991. Today, nearly a billion websites are online and the complexity of them (not to mention the complexity of the ecosystem they constitute) only continues to grow. There are hundreds of advanced programming languages, which all do the same thing: communicate with a computer. With hundreds of languages to understand, you can imagine it’s quite a process for computers, systems, and people to keep up with. There came a time when the savvy folks at Yahoo, Bing, and Google realized a bit of structure and organization was needed or else things would only get farther out of hand. It had become a bit of the Wild Wild West.

Metadata: A card catalog for search engines

“Metadata” is information that tells what data is about; i.e., data about data. Remember the old card catalogs in libraries? The card catalog indexes cards that tell specific things about all the books in the library in a standardized way. The cards include data such as the title, author, and publication date. This data is used to generate a unique call number based on the Dewey Decimal System. This is a set of standards used to index each of the books in a library, to ensure that books on the same subject can be found near each other, in a predictable order. The Dewey System has been used since 1876!

What is schema?

In the context of the Internet and over-simplified, “schema” is a way of structuring and organizing metadata. In mid-2011, the three largest search engines came together in an effort of collaboration never seen before: Google, Bing, and Yahoo initiated the creation of a set of standards for website metadata. Before the year was out, they were joined by the Russian search leader Yandex.

The search engines formed, with the goal of defining and encouraging the adoption of an agreed-on structure (and similar vocabularies) that webmasters and others could use to mark up website content. The result would be that search engines (and other systems) could more easily and accurately understand what a website was about, and information could be more findable.

How schema works

As the website notes about its shared vocabularies, “These vocabularies cover entities, relationships between entities and actions, and can easily be extended through a well-documented extension model. Over 10 million sites use to markup their web pages and email messages.”

People, places and things each are represented on a page and schema acts to define them consistently across the web. Simple elements such as location and contact information, as well as complex elements like ratings are streamlined and consistent with language. Here’s an example of how structured data displays to the reader looking at movie search results: …and here’s how the site displays some of the same information to the search engines:

Here’s another movie example, which illustrates how schema can help a search engine understand what a website is about. The word “avatar” can mean many things: an online representation of a person, a famous movie, or an unrelated television series. It’s also a brand of discontinued aftershave. If you collect antique men’s fragrances and are looking for Coty’s Avatar, the schema on this page tells the search engine this is the right page to return, not one of the vastly more popular pages about the movie.

Metadata makes the difference. It’s used behind the scenes in the HTML of a site, throughout the site, to define its contents and context. For search engines this information is the fuel that makes a search engine run. Without context and understanding a search engine can still work, but it can’t analyze a website as accurately. This means it can’t qualify how that site might answer a searcher’s question as well, which in turn means it may be less likely to return that site.

Have you ever wondered how those little blue links show up in Google search results, like the second entry here?

Or why some results have ratings and others don’t for example? Or, how about why some results show as expanded in the search results pages when others don’t? This is the magic of schema and microdata.

Types of Schema

Many types of schema are used; thousands exist and more continue to be developed. It can be a bit confusing to navigate the landscape.

First, start with the right type of schema for your needs. In order to determine the best type of schema to implement it’s important to understand all your options and the types of schema available. Let’s look at the most basic:

  • Thing – Defining a “thing” can consist of any number of generic items. This includes specific microdata for images, text descriptions and alternate names for example. It is the most generic type of schema item.
  • Event – An event that may happen at a specified time and location can use specific schema data to share information such as the duration of time, end dates, ratings, organizing party and much more.
  • Person – schema data to define elements of a person including address, affiliation, address, birthdate, and death as well. Real or fictional schema data is available to define the characteristics of a person in microdata form.
  • Place – A physical location can be defined with microdata such as property information, address, store codes, global location number, longitude and latitude, and a URL to location map. These metadata items help define where a business is located.
  • Product – Schema available to define products such as item names, product ratings, offers, size of product, type of good and more. Microdata which aids in understanding more about a product and service a company may sell on or offline.
  • Organization – Microdata defining elements of an organization including address, area served, awards, brand information, contact individuals, emails, tax IDs, phone, publisher (if applicable) and more.
  • Review – Define all elements of a page that discusses items to review. From reviewing a product, service, or entity to the elements of a review such as author, character, citation, and content rating are defined with the review schema.

What’s microdata?

Here’s where the common vocabularies come into play. Microdata vocabularies provide the semantics, or meaning of an Item.

Google defines microdata nicely: “Microdata is a specification to embed machine-readable data in HTML documents. Microdata consists of name-value pairs (known as items) defined according to a vocabulary.”

Here are examples of common name-value pairs in one vocabulary: provides examples in four formats: without markup, microdata, RDFa and JSON-LD. For developers and webmasters this is an incredibly helpful resource.

Implementing Schema

Hopefully, if you’ve made it this far, you understand the types of schema and what it can offer for search engines. Now comes the time to actually implement schema. Where do you start?

Determining the opportunities for schemas used on your site is a two pronged process. First, you’ll want to determine the actual schema you’d like to test. If you’re trying to add location data, or maybe give data about events, choose an item to implement.

Next, implementing schema will require a bit of knowledge about your website platform, whether you’re using CMS or some other solution. Adding code onto your site is not for the faint of heart, and should be left to the professionals. Have a conversation with your webmaster or digital agency, tell them the types of schema you’re looking to implement and ask if that is something they can help you implement. You’ll earn some extra kudos if you even give them the code to implement (see the code generator below).

Some resources are available which will provide beneficial information on implementing schema. Some plugins are available for CMSs like WordPress, which may not require as much actual coding. Work directly with your technical team to implement this extremely useful and valuable tool.

Additional Resources Welcome to

GitHub: Resource Schema

Schematron: Schema Resources

Google Developers: Schema: Insert

Google Developers: Schema for Video

Schema Creator:

WordPress: All-In-One Schema

Drupal: Schema

Implementing Resources

Kissmetrics “How to Boost Your SEO by Using Schema Markup”

Moz’s “ Structured Data”

Not sure where to get started? Have a question about Schema? Ask us in the comments below!