Hello, ladies. Look at you interface for creating linked data:
Now back to an interface used for creating linked data at Facebook:
Now back at your interface. Sadly, it not like the one from Facebook. Why is that?
The concept of linked data has its page on Facebook. It is identified by the URI http://graph.facebook.com/103761322995229, which is based on the identifier in the Facebook URL (103761322995229). The numeric identifier may be replaced by a “nice”, human-readable string, when the page reaches at least 20 likes. Given the concept URI, one can dereference it to retrieve its RDF representation:
curl -H "Accept:text/turtle" http://graph.facebook.com/103761322995229
Bearing in mind the linked data best practices, it would be even better if there was a redirect set up from the original Facebook URL to this URI. Nevertheless, the important thing is that one can reference Facebook resources from their data. Having Facebook resources equipped with dereferenceable URIs makes them linkable.
Facebook's Open Graph Protocol features a property likes (URI: http://graph.facebook.com/schema/user#likes) that can be used for relating a resource to an object that the resource likes. The auto-generated, yet human-readable reference for the vocabulary can be found here.
Taking this into account, the act of clicking the Like button for the concept of linked data while being logged in as me (URI: http://graph.facebook.com/jindrich.mynarz) can be treated as equivalent to writing the following triple (in Turtle notation):
@prefix graph: <http://graph.facebook.com/> .@prefix fbuser: <http://graph.facebook.com/schema/user#> .graph:jindrich.mynarz fbuser:likes graph:103761322995229 .
Note: the dot character (“.”) is not allowed in local names (such as jindrich.mynarz) in the original Turtle specification, however, in the newer version of the specification it is possible to use it.
It is likely that Facebook stores data differently than in this way, however, as can be seen in the case of Facebook pages and users, in some cases Facebook can surface the data in RDF. Such assumption can be supported by the practice of using RDF as an exchange format.
What I wanted to show by this example, is that by clicking a Like button, you are in fact creating links. Liking is an example of a speech act in which a subject expresses its relation to an object. The subject of the link is the agent (i.e., you, the person acting) and the object is the web page shown.
Using the Facebook Like button is an example of expressing how users feel about something. Facebook allows to express various feelings about things. Apart from the most known liking, users can recommend, or, thanks to the recently introduced Facebook actions there is an extensible mechanism for creating new types of relationships that users may describe. Facebook sees this functionality, and quite rightly so, as the “building blocks of Open Graph” (source).
What this reflects on, is the growing opportunity for crowdsourcing linking. Facebook Like button serves as an example of an easy-to-use interface for creating linked data that is available for masses. It shows the potential of adding more complex and machine-readable annotations via simple interfaces. It is a tool for growing the interconnected web of data, describing how do the users of the Web relate to its contents. Not to forget that the users of the Web might be machines too. Imagine bots crawling the Web and clicking Like buttons, leaving their traces on the visited places, and you will start to see the possibilities of crawlers connecting the web of data.