Follow-up of +Danny Ayers
, here is a proposal for a star rating for linked data vocabularies
★ Publish your vocabulary on the Web at a stable URI
★★ Provide human-readable documentation and basic metadata such as creator, publisher, date of creation, last modification, version number
★★★ Provide labels and descriptions, if possible in several languages, to make your vocabulary usable in multiple linguistic scopes
★★★★ Make your vocabulary available via its namespace URI, both as a formal file and human-readable documentation, using content negotiation
★★★★★ Link to other vocabularies by re-using elements rather than re-inventing
More on the blog post on why your ★★★★★ data need ★★★★★ vocabularies.