The closing keynote at XTech 2008 saw Sean McGrath discussing “Orang utans, Oxen and Ogham Stones“. The central premiss of the presentation is that as the web becomes more dynamic so more and more of the data is only accessible when its requested – and this can mean that its inaccessible to machines and therefore the rest of the web. There are no persistent documents.

Sean argued that we have three models operating on the web.

• Model A is the platonic model. Documents (already) exist on the server – you simple request them over HTTP.
• Model B has documents existing on the server but are dynamically rendered transforming the content in the process using, for example, CSS and JavaScript.
• Model C has nothing existing until you observe it. The document is composed and rendered when requested – Just In Time programmatic generation of content.

Model C is Turing complete, user-sensitive, location-sensitive and device-sensitive and model C is winning at least on the client side with Ajax, Flash, Silverlight and Air. It’s now relatively common when viewing the source of pages and see no actual content, just JavaScript to generate the content.

So does this matter? Sean thinks so yes. He fears that this data is siloed, trapped within the code and not accessible via addressable URIs. And if we lose URIs and hypertext then we also lose deep linking – and what about search engines? Will the Googlebot download that JavaScript and eval it to spider it? And what about everyone else? URLs are great for wombling – they can be bookmarked, tagged and mashed-up.

If Sean is right then rather than the web being made up of documents with some code (as it once was) we will be left with a web of few documents and lots of applications. A Web which is really just HTTP.

But is this all true? I’m not so sure.

Sure there has been a rise in the use of client side scripting to dynamically render content (notably with the rise of Ajax web apps) and there are plenty of server side applications delivering dynamic content – but I don’t think we should be worried about server side apps, as long as they are well designed.

It seems to me that we have three classes of webpage:

• Resources – individual objects, which if designed well live quite happily at persistent URLs;
• Aggregations – listings and groupings of those resources;
• Web apps – pages that let users manipulate resources.

So for example even though the BBC Programmes is rendered dynamically (from a server side application) the resources are found at persistent URLs and the pages contain lots of lovely, semantic, mark-up (there are are also plenty of aggregations). Whereas Flickr uses Picnik a client side photo editing application to let Flickr users edit their photos.

Is this a problem? I don’t think so, no. After all, as Sean noted there’s no such thing as a resource only a representation of one. And this is the best you can ever get – the web is made up of URIs and HTTP. We just need to be careful not to lose sight of the importance of URIs.

Photo: good ol days, by emdot. Used under licence.