It's a shame that the best rendition of Tim BL's star rating system for linked open data is the one that appears on a mug! The version in the text of W3C's Linked Data Design Issues page is somewhat messy (and not all that citable)!

I'm working on something at the moment that is using the star system. Here's my version. It's somewhat more wordy but describes each star more fully and in a stand-alone way:

• 1 star - Data is available on the web in any format (e.g. HTML, PDF, MS-Word, GIF, JPEG) and under an open licence
• 2 star - Data is available on the web as machine-processable structured data (e.g. MS-Excel) and under an open licence
• 3 star - Data is available on the web as machine-processable structured data using non-proprietary formats (e.g. CSV, XML) and under an open licence
• 4 star - Data is available on the web as machine-processable structured data using W3C ‘semantic web’ standards and URIs to identify all key entities (e.g. RDF, SPARQL) and under an open licence
• 5 star - Data is available on the web as machine-processable structured data using W3C ‘semantic web’ standards and ‘http’ URIs to identify all key entities (e.g. RDF, SPARQL), under an open licence and linking the data to other people’s data (using their ‘http’ URIs)