{"id":173,"date":"2010-04-16T07:21:00","date_gmt":"2010-04-16T07:21:00","guid":{"rendered":"http:\/\/www.sgmlguru.org\/wp\/?p=173"},"modified":"2015-01-14T18:35:24","modified_gmt":"2015-01-14T18:35:24","slug":"permanent-urls-addresses-and-names","status":"publish","type":"post","link":"https:\/\/www.sgmlguru.org\/wp\/?p=173","title":{"rendered":"Permanent URLs, Addresses and Names"},"content":{"rendered":"

I found a link to an article by Taylor Cowan<\/a> about persistent URLs on the web. It was mostly about what happens to metadata assertions (such as RDF statements) when links break, but there was a little something on persistent links and URNs, too. A comparison with Amazon.com<\/a> <\/i>and how books are referenced these days was made. A way to map the ISBN number as a URN was described (URN:ISBN:0-395-36341-1<\/i><\/b> was mapped to a location by the PURL<\/i> service, in this case at http:\/\/purl.org\/urn\/isbn\/0-395-36341-1<\/i>), which is quite cool and, in my opinion, both manageable and practical.<\/p>\n

The author thought otherwise, however: But on the practical web, we don\u00e2\u20ac\u2122t use PURLs or URNs for books, we use the Amazon.com url. I think in practical terms things are going to be represented on the web by the domain that has the best collection with the best open content.<\/q><\/p>\n

Now, what’s wrong about this? At first, it may seem reasonable that <\/i>Amazon.com<\/a>, indeed the domain with the (probably) largest<\/i> collection of book titles, authors, and so on, should be used. Books are their business and they depend on offering as many titls as possible. In the everyday world, if you want to find a book, you look it up at Amazon.com<\/a><\/i>. I do it and you do it, and the author does it. So what’s wrong about it?<\/p>\n

Well, Amazon.com<\/a> does not provide persistent content per se, they provide a commercial service funded by whatever books they sell. At any time, they may decide to change the availability of a title, relocate its page, offer a later version of the same title, or even some other title altogether. The latter is unlikely, of course, but since we are talking about URLs, addresses<\/i>, rather than URNs, names<\/i>, talking about the URL when discussing what essentially is a name is about as relevant as talking about the worn bookshelf in my study when discussing the Chicago Manual of Style<\/i>.<\/p>\n

Yes, I realise that my example is a bit extreme, and I realise that it’s easy enough to make the necessary assertions in RDF to properly reference something described by the address rather than the address itself, but to me, this highlights several key issues: <\/p>\n