Terms like semantic web, the social graph, and machine readable link relations are things that people in SEO and marketing typically sorta know about but don’t have a clear grasp on. I want to quickly explain a couple of terms and concepts that are part of the social future of the web and how link relationships can define more than we think. It will take a few posts to do so. Let’s start with XFN and defining link relationships.

Link Relationships:

When we think of a link we tend to think of a “vote” that makes our web properties stronger. Link relationships actually can be machine readable and defined. We all are familiar with “nofollow”, which is entered into links as [rel="nofollow"]. The “rel” part of that stands for “relationship” – as defined by the W3 here.

The only link “rel” that is widely used in the SEO community is the “nofollow” one. This occurs mostly due to Google via Matt Cutt stating that paid links must be”machine readable”.

If links are so important to SEO, then why doesn’t SEO define the relationships of their links?

Links that use XFN are a machine readable (ie Googlebot) way to define links. In other words, while many of you are worrying about changing anchor text around to make your links more natural, you are ignoring the actual existing machine readable way to do the same thing.

XFN

XFN is a standard of social link relationships. Who cares? You do, silly.

XFN and FOAF are really old things but one of Google’s newest API’s is called the Social Graph API and relies on XFN and FOAF data. XFN stands for Xhtml Friends Network.

XFN is the way that social link relationships are defined. In other words, instead of [rel="nofollow"] this new social API relies on things like [rel="friend met co-worker"] which means that I am linking to “a friend who I have actually met who is also my co-worker”

To create XFN machine readable links is pretty simple and we will discuss and illustrate why you might want to start doing it later, but for now let’s see what you can do with XFN. (if you are reading this via feed you won’t be able to see it, so come on over to the site) With this tool you can enter info about your link and define who or what the link is to you. So if you are linking to me for example you would put “Patrick Sexton” in the name field, and then define the rest by choosing which options apply to me…

note: The above tool was created by Matt Mullenweg and modified by me to be widget sized.

The XFN link tool is a really great overview of what relationships can be defined. Friend data, professional data, and even romance data can be defined.

Google Social Graph API

The Google social graph API identifies and displays social connections between links, websites, and people. Most interesting to me is the way the documentation spotlights XFN and FOAF (we will talk about foaf in another post). If Google is basing APIs on XFN and FOAF then that is about as clear of an indication that you can get from the search giant that it is using, and planning to use XFN and FOAF data.
If Google is using XFN, then you may want to know about it.
I will make SEOish “XFN friendly” and when I do I will take some screen shots and create a tutorial, but it is really very simple to do.

XFN Resources

To learn more about XFN go here
To make your site XFN friendly (in four steps) go here
To get the XFN link tool gadget go here

Social Graph API Resources

The API is here