If you work on the net then you'll have probably heard of the "semantic web", it's nice, you can ignore it and get along just fine though; however "Linked Open Data" (LOD) is now upon us and it's one of these things that can't be ignored, no matter which sector of the internet you work in, if you do ignore it you'll probably become extinct (career-wise) pretty soon.
Sounds melodramatic but the whole point of this text is to explain in real terms the effect it'll have on the every day web worker; the web developer, web designer, seo expert, internet marketer etc. So that you, my current or future friends and associates still have a job in a couple of years; and I researched it so that I would still have a job in a few years (+ because I love this stuff!)
A bit about Linked Open Data (LOD).
LOD can easily be a huge, scary and new thing, overwhelming in so many ways with all this talk of a cloud, billions of bits of information in some part of the web that is separate to "us"; take one look at the diagrams of the linked open data cloud and you'll see those academic acronyms of scientific organisations, future thinking global entities publishing their specialised data - nothing about you and me with our little blogs, and moreover nothing about our clients websites.
Sure it's about getting massive amounts of data on the web, linked and open for use, but it's different to how you expect :)
Linked Open Data is simply about making the info we already put on the net (like this post) machine readable as well as human readable.
It *IS NOT* about creating some system to dump everything from our database in some weird format for a machine to read somewhere.
It *IS* about wrapping the data on a normal page in a bit of markup so that a computer knows what it is.
If you're writing about london you simply add a tiny bit of markup that says 'about="http://en.wikipedia.org/wiki/London"' - honestly that's it in real terms, the user reading your page knows its about London, England - and now a system like google knows that it's definitely about London, England too. In most cases though it's simpler; it's a case of saying this article is titled "x" and made by person "y" - that alone makes a huge difference to the net.
How LOD will change the web.
More Links! We're currently in the age of search, if you want something you search for it, to get more info you search again, and again and so on.
Link trust was at an all time low a few years ago, sure you'd click a navigation link on a site but not a link in a document, because it was probably to a popup, an advert, something you didn't want. Not now though, mainly thanks to bloggers with their in text links to other pages, the world has grown to trust the link again.
Linked Open Data will spawn a massive increase in related data on page, related resources, articles, images, videos and more. And thus many, many more links.
This means that people will search less, and explore more; ever increasingly.
It's unavoidable, and even if a website isn't enhanced with all this extra linked data, odds are the user will have a browser extension or app running that will show all the related information anyway - these technologies are already here and used - adoption *will* grow, no way out of it, change happens.
Info for specific sectors
This isn't the meant to be a full introduction or all encompassing, in fact nowhere near it - if you want the ins and outs of LOD then look elsewhere. This info is for the everyday Web Developer, Web Designer and SEO Specialist.
Web Designers (+ those who work with html)
To be honest I think this change might hit you guy's hardest; you see XHTML+RDFa is already here, it'll be massive soon (and don't go thinking HTML5 will get you out of it, RDFa will be in there too). In short XHTML+RDFa is xhtml as you know it, but with support for embedded RDF information, really it means a few new properties on elements that let you say what they are; in place FOAF, Dublin Core (DC) and the like. Any further description is outside the scope of this document ;)
What this means for you is that as well as having potentially a lot more to display on page (linked data) and lot's of UI challenges, you also now have to cater for this RDFa data in your templates. It's not like other W3C stuff which you can ignore, different to cross browser compatibility, if you leave it out or skip the RDFa stuff then the site will potentially be outside of the LOD network, traffic will drop and ultimately the site may as well not be "in" the web (might be a few years before that though) - so in many ways the end of ignorance and excuses.
You can currently slap out some HTML4, change the doctype, stick on jquery and make it "look" web 2.0 - and people will think it's web 2.0; with web 3.0 (the linked open data based net) you can't do that, it either is web 3.0 or isn't; there isn't a "web 3.0" look, just web 3.0 source.
Drupal 7 has RDFa support out of the box; within the year I bet every CMS & Blog will too; and if you make a new template with the RDFa cut out because you "don't know it", then I'm pretty sure it won't be long before your clients or employers cut you out; and we don't want that.
Further, if you don't - developers will be on your back big time & changing your source; or worse the SEO guys will be ;)
Web Developers
All of you need to know what triples are (subject-predicate-object), and URIs and CURIEs (not your normal URIs, URIs as Identifiers).
If you're going to be exposing data in your systems then you need to get used to mapping database properties through to RDF triples; that a user is a foaf:person with a foaf:name; that tags are ctags and dc:subjects, and that articles have a dc:title (keeping it simple for this).
If you're going to be consuming LOD data then you need to learn a bit more, RDF, SPARQL, Owl, ontologies and a bit more.
And if you want to get "in to" LOD in a big way, then go do it.
SEO Specialists
You need to know what the designers know, and you'll be changing from SEO specialists to data exploration optimizers or suchlike, focus will be on how you can make the data machine readable and get it linked in by the right services.. should be fun!
Further, you'll need to watch for how to get traffic to the sites, as mentioned search engine traffic will drop slowly over the next few months and years; with more focus going on "links" from related pages. As for the diggs & reddits, who knows how it'll effect traffic from them.
Summary
IMHO it's in all of our best interests to just get on with this, it will happen and the sooner YOU do it and convince your employers you have to make this move the better, companies can easily loose clients too if your competition is offering "web 3" and you aren't.
At no point have I seen a tech hit the web which could literally leave people behind if they don't jump on board; it's happened in other industries and now ours (remember VHS?).
The two questions most people / companies / clients will immediately raise..
1] We don't want to expose all our data for reasons X,Y&Z!
LOD isn't about exposing all the your data on the internet; it's about making the data you've already exposed on the internet in a more granular fashion, it's about making that data machine readable.
Presently you may have an article on a page with a title and author credit in HTML, in the future you would still have the same author and title, however they would be wrapped in markup that allows a machine to understand that "Joe Blogs" is a person who is the author of the article, and that the articles title is "I'm scared of exposing my data".
If you consider you're public facing web pages, everything on that page is already exposed, all we're doing here is describing what each bit of data is in a way we can all use.
2] Trust & Junk
One common misconception is that you have no control over the source of the data you pull from the "cloud", and that it could essentially be junk. However this couldn't be further from the truth, what we do is to find a source of data we trust that has their data exposed in a machine readable format, then query it for the exact information we want, and finally include or display it in our own system.
To illustrate, consider you wanted to reference the countries of the world with population in your system. Currently you would have to build a database table, populate that data with country name and country population, then write some code to display that data. In this scenario you'd probably get the population data from a credible source such as wikipedia (copy and paste it in to your own database).
By using linked open data, you could treat the machine readable version of wikipedia (dbpedia) as your database table, query it instead and again write some code to display the data on you're own site.
You're displaying the same data, from the same trusted source; and you've selected which source you trust; it's not a case of just querying some cloud of data; it's a case of choosing which source(s) you want / trust and querying them.
As an additional bonus you don't need to worry about your information going out of date, as you're getting the data straight from source, the population of each country is updated on your site whenever it's updated on wikipedia.
Further, you don't need to worry about maintaining that list of countries, as in a single query you can pull out a list of all countries with each ones population, as the world grows and changes, so does your data.
Further still! once you've made the move to using some linked open data, all the data you could want is at your finger tips, let's say a decision is made to include 30 different bits of information about each country in your system. Consider that task for a minute - full system change, finding, collating and entering all that data; let alone maintaining it! Well, I'm sure you can guess the next bit, using LOD we can simply expand our original query to include the other bits of information we want, then display it - job done.
That's it.
Good Luck!
nathan
