The Internet Content Rating Association (ICRA) is changing the way it ranks websites. 

The new system will use Resource Description Framework (RDF) technology developed by the World Wide Web Consortium, which allows website developers to grade their sites according to the suitability of the content.

For example the new system allows clearer differentiation between medical and pornography sites, and includes shortcuts to generate labels for pornography and gambling sites. 

"RDF is a modern technology with an active and growing body of support from academia and the digital content production and distribution industries," said Stephen Balkam, chief executive at the ICRA.

"With digital content now flowing freely across national boundaries, media platforms and delivery devices, this new system will allow ICRA and its partners and supporters to deliver better child protection, along with a significantly improved means of self-regulation to the industry on a global scale."

RDF allows new areas of the internet to be classified, such as RSS feeds and blogs, and the technology forms a significant part of the Semantic Web being developed by Tim Berners-Lee.