This article presents the top-level of an ontology categorizing and generalizing best practices and quality criteria or measures for Linked Data. It permits to compare these techniques and have a synthetic organized view of what can or should be done for knowledge sharing purposes. This ontology is part of a general knowledge base that can be accessed and complemented by any Web user. Thus, it can be seen as a cooperatively built library for the above cited elements. Since they permit to evaluate information objects and create better ones, these elements also permit knowledge-based tools and techniques – as well as knowledge providers – to be evaluated and categorized based on their input/output information objects. One top-level distinction permitting to organize this ontology is the one between content, medium and containers of descriptions. Various structural, ontological, syntactical and lexical distinctions are then used.