I was looking for a Stack Exchange site to ask this and Open Data seems to be the one.
I am to write a short note on how to find information on the internet and for that I would love to read a taxonomy of internet sites, or, to talk this site's language, a taxonomy of open data sources. What are their properties, how can one use their data and how can they be found if one has a special query. Search sites does not necessarily help at the first attempt.
Is there one?