Before diving into RDFa (Resource Description Framework-in-attribute), we should understand the monumental importance of SEO (Search Engine Optimization) for all sites looking for new, or more, visitors. SEO is often underestimated because it is not a sexy Web technology like cloud computing or the Semantic Web. Plus there are a number of "black hat" techniques that have evolved around SEO, which have turned some people off to SEO.
To understand the value of SEO, imagine you have a business. Let's say you own a store that sells watches. There are a number of different types of people in the world and your theoretical goal is to turn them all into customers. Let's examine the different perspective customers out there:
* People who never wear watches
* People who wear watches, but don't need to but new watches
* People who wear watches and need a watch
* People who are currently actively seeking to buy a watch
* People who are shopping for a specific type, style, and price range of the watches that you are selling.
I will use this analogy throughout the article to examine when SEO is appropriate and when RDFa is useful.
First, Consider Different Search Engines
At the time of writing this article, there are three main players in the search game who own about 98 percent of all search market and the other 2 percent generally just copy the big three in how their algorithms work. In this article we'll focus on the big 3:
* Google -- undoubted leader, most mature search technology on the planet and by most accounts, trumps Bing and Yahoo
* Bing -- Claims to be semantic, but compared to Google side by side, in most metrics does not come close to Google
* Yahoo -- actually getting out of the search game and planning to use Bing technology as its search engine as early as late summer or early fall 2010
Even though there are three major search engines now, moving forward there will only be two, because Yahoo is consolidating its search with Bing. Plus, since Google is much better than Bing in the first place, and by many accounts, for Bing to improve it will need to copy more of what Google is already doing, we can just focus on SEO for one search engine -- Google.
First Page of Search Results and Rich Snippets
RDFa helps search engines add something called "rich snippets" to appropriate items within the ten sites that come up after a search. The rich snippets are small visual cues to the person who sees the search results, increasing the click-through rate of that search result over the others, often even over those which are ranked higher on the page. It is important to keep in mind that Google never say that it gives the site a higher ranking for using RDFa, but only adds the visual cue.
This means that webmasters should still have as their goal to rank within the top-10 sites because few people see the items on the second page of the search results, even if it may look nice. Here are very approximate click-through rates of the items on a Google results page. These of course vary with the topic of the site, competition for that particular search term, and a number of other factors.
* 1st -- approximately 20 percent click-through rate
* 1-3 (visible on most screens without scrolling down) approximately 15 percent click-through rate
* 4-6 -- 11 percent click-through rate
* 7-9 approximately 5 percent click-through
* 10 -- under 5 percent click-through
* 2nd page under 1 percent click-through
From that simple breakdown it should be obvious that sites need to distinguish themselves from the other 9 on the page to increase the click-through rate. Traditionally this has been done with a good title and a description. With RDFa, Google offers webmasters the ability to make their site stand out even more. Consider for example that you are a restaurant site and you come up in a search for a restaurant. If you use RDFa, Google will display your restaurant's star rating. This will add color and images to your appearance within a search, greatly improving your click-through rate.
Sites often report a 15-30percent increase in the click-through rate after Google shows the visual cues next to their site in the search result.
When you first start your page, you want to declare which ontology you will be using.
version="XHTML+RDFa 1.0" xml:lang="en">
Line 2 declares that will be using the FOAF (Friend of a Friend) ontology to identify people.
Line 3 declares that we will be using the Dublincore ontology to identify document elements
Within our HTML body, we may do something like this:
Important Title Goes Here
This will tell Google that this is a title (although Google should already understand that)
You can also link a person's email address using the FOAF ontology like this:
There are a number of things you can do with RDFa, but it can sometimes be difficult to know what will work and what won't until you actually implement it on your page and see whether Google will decide to add rich snippets to the search results. Nothing is guaranteed and Google reserves the final say on how they will view the RDFa.
More Examples with RDFa in Italics:
Job title: <span property="contact:title">The Boss</span>
<a rel="contact:email" href="mailto:name@someEmail.com">Email Me</a>
Semantic Web and Trust
Some people dream of some unified Web, and hope that RDFa will bring them one step closer because it links and unifies a number of concepts on the Web. RDFa allows people to tie in structured vocabularies recognized on the Web to describe various elements of your site like a person or a product.
Yet we should be careful not to confuse things and keep things in perspective. Most importantly, RDFa is not content. RDFa is an underlying markup language. That means RDFa can be manipulated by spammers or ambitious webmasters who try to trick Google into thinking that a site is about some product, person, or an important subject when in reality the content of the site does not support that. Google publicly states that it uses about 200 metrics to determine the ranking and look of the search results. RDFa would tie into just one, or in the best case a handful of these metrics and there has been no sign that the role of RDFa is large. Google does not tend to put too much emphasis on markup and instead focuses on the quality of the content.
The only large benefit of RDFa is when Google trusts the site enough to display the rich snippet, which as we discussed, can significantly increase the click-through of a search result. And this only happens when Google trusts the site and thinks that displaying the rich snippet would be relevant for the particular search string. RDFa may also help build a site's trust by containing widely recognized things marketed up by RDFa. But then again, Google never discloses such details of their algorithms and as we know, Google does not always regard pure markup very highly.
Relevance is really key because without relevance to the consumer, the products and content are useless to them even if they do come to your site or store. A person looking for food might pass by a store that sells watches. Even if there is a sign that says "Free Watches" the person may look because it is relevant to their "like to get a good deal" side, but the real interest only comes if the person is actually looking for watches.
Sellers often try to create relevance by adding "FREE" or "50percent OFF" to get attention because that creates pseudo-relevance for people who like to get a good deal on things (and who doesn't?). Fortunately, correct application of SEO is a savior. Not only do business owners no longer have to blindly attract random prospects, but site owners are able to create extremely relevant and highly targeted landing pages for people with very specific needs.
For example, people who are looking for green watches with pictures of butterflies will have to look for a very long time to find such a specific item. Demand is obviously low for this product, but so is the competition. If the watch store owner made a page exactly for selling these types of watches, not only would people searching for such an item have a very high conversion rate from prospects to clients, but also would not mind paying full or even inflated prices. Not to mention it would be easy to rank high for such a targeted search.
Future of RDFa
As the Web matures and some concepts become more unified and trusted, things may go in a number of directions:
* Either Google and other search engines will be more able to provide rich snippets even without RDF just because something is pretty commonly recognized on the Web or,
* RDFa and structured data will be looked at with higher trust and regard (which is the hope of the Semantic community), helping search engines rank them higher and show rich snippets with less chance of spam.
While there is some excitement about RDFa within the Semantic Web community, I'd caution that, to be trusted and relevant, a much better approach than having RDFa or some other markup is to actually exert effort into being trusted and relevant by providing high quality content and not hope that a markup language will help you cut corners. Yes, I know that is a frustrating slogan that is repeated over and over, but the truth is that search engines are getting smarter and there are less tricks and shortcuts that will work. Search engines, just like people, want high quality content and are getting better and better at recognizing it every day.