The Rise Of Structured Data And SEO
It all started with a friend. rel="friend" to be exact.
In 2003 at SXSW Interactive, Tantek Çelik proposed
the use of rel="friend" for blogroll hyperlinks. About a year later, the nomenclature
for structured data in HTML was born
and dubbed "microformats." Microformats are
HTML attributes that are added to
existing elements. The attributes don't affect what people see when a Web page is
rendered, but provide structured data to machines. What that means is that you can
include contact details, events, reviews and other types of data, and search engines
will be able to easily comprehend its meaning.
While structured data may be new to many search engine optimizers, it's actually
been around for quite some time (at least in Internet years.) It's important to
understand where structured data came from and where it's going, because it's poised
to dramatically change how all sites communicate with search engines.
Creating the real Web 2.0
Let's go back to the early 2000s. The year after that SXSWi proposal, Tantek
and his friends refined and developed different microformat standards, including
XMDP, XFN, RelLicense, RelTag, RelNofollow, VoteLinks, XOXO, hCard, and hCalendar.
Technorati was an early leader during the
development of microformats, and in March 2005 Tantek Çelik and
Adam Rifkin wrote a microformats document on
the Technorati developers wiki.
Shortly after the microformats wiki went live on Technorati,
Ryan King declared structured
data formats an "evolutionary
“I think what we're seeing is a stage of evolution which will have revolutionary
For those early leaders and others, microformats were about creating the semantic
Web, what they referred to as the real Web 2.0. About two months later, on June
20, 2005, microformats.org launched as a central location for the structured data
Adoption of Structured Data
Early adoption of microformats was very slow, supported mainly by Technorati
and semantic enthusiasts. Google was an early adopter in 2005 with the infamous
rel="nofollow." Yes, that's a microformat. It started to gain more traction and
exposure after it was integrated into WordPress and other high-profile sites like
Magnolia (now defunct.) E-commerce sites like
Williams-Sonoma added the hProduct
microformat to its product pages, and Yahoo! began using hCalendar for event pages
But it wasn't until
Google debuted Rich Snippets in May 2009 that structured data gained recognition.
From that point on, it was only a matter of time until structured data would become
a standard for communicating with machines, and in particular, search engines.
In late 2009, Google
began testing a new kind of structured data called
microdata. Microdata is a feature of
HTML5 (now known as "Living
Standard HTML".) Similar to microformats,
microdata uses attributes inside of elements.
“At a high level, microdata consists of a group of name-value pairs. The groups
are called items, and each name-value pair is a property. Items and properties
are represented by regular elements.”
Microdata appears to be the grown-up and refined version of microformats. Think
of it as more structured structured data. The key item attributes are "itemscope"
and "itemprop," accompanied by supporting attributes like "itemid" and "itemref."
With the exception of itemscope, all microdata attributes have values associated
The appeal of microdata over microformats has to do with its tight integration
into the living standard HTML and
its ability to have values easily expanded. I have no doubt that this is the reason
Google, Yahoo! and Bing chose this standard for their new structured data initiative,
Schema.org picks up where microformats left off. Schema types are hierarchical
and can have multiples parents when expanded. There are currently two top-level
types, "DataType" and "Thing." DataType includes sub-types, like dates, numbers
and text. The Thing type is much more expansive and includes sub-types ranging from
recipes to events. The full list of types is available at
Structured Data and SEO
Is structured data going to affect search engine result pages (SERPs)? Yes, and
it already does.
Thanks to rich snippets — the use of microformats or RDFa markup — structured
data already affects SERPs. Searching on Google for "beet salad" returns a list
of beet salad reviews and recipes. You can even include and exclude ingredients
to refine your search. All of this is possible because of rich snippets, and the
top search results are dominated by sites that are using them.
Structured data allows search engine optimizers to provide explicit semantic
meaning to their data. Coupled with structural elements from the living standard
HTML — nav, aside, article, section,
header and footer — SEOs have an entirely
new arsenal for communicating content to search engines.
The beauty of adding structured data to Web pages is that it provides targeted
exposure for your content. In the same way that Google appears to show preference
for sites that utilize rich snippets, one can assume that the same will be true
The use of structured data, like Schema.org's "types," will also go well beyond
the reach of major search engines. Since it's an open format, expect to see innovators
creating niche vertical search engines and services that primarily rely on microdata
and other structured data formats.
The use of structured data has been a long time coming, and it's exciting to
finally see it being widely adopted. SEOs
should start to become very familiar with structured data formats like microformats
and microdata if they haven't already. Otherwise, they'll risk becoming obsolete.
Jon Henshaw is product manager at Raven Internet Marketing Tools and a frequent PubCon speaker. You can read his full PubCon biography here.