Companies develop and maintain complex web sites. Literature provides them with many guidelines for these tasks. However this knowledge is disseminated in many information sources and difficult to apply. This paper is an attempt to address the following research question: How to structure the existing guidelines helping website designers in order to facilitate their application? The contribution is twofold: i) we propose a meta-model allowing a rich representation of these guidelines, ii) we feed this model with several hundreds of guidelines thanks to a deep extraction and structuration. Future research will consist in enriching the UWE (UML-based Web Engineering) method with this knowledge base leading to a quality based approach.