I know that the subject of custom web URL file extensions has been talked about before, mainly within the context of SEO. Also, the discussions have normally been about having one single custom extension throughout the site.

However, I recently noticed that a major British newspaper has started using unique 'page extensions' (and I use the term loosely here) for each page on the site. For example a story about green widgets, might go under the URL:

http://www.example.com/business/2008/aug/16/widgets.greenwidgets

I just wonder what people thought of this approach and what might be the newspaper's intention? Is it merely a cataloging/content management decision? I can't imagine any perceived SEO benefits being the inspiration (indeed I wonder if there may be any negative indexing side-effects?)

And does this mean anything in the wider context of the new top-level keyword domain names? Is keyword branding within URLs about to become more important?