We made the Dewey Decimal Classification system summaries available for open use a while ago on the ResearchWorks website (the top three levels). I am not sure how widely noticed this was.

The Dewey Decimal Classification (DDC) system uses simple decimal notation to divide recorded knowledge into 10 main classes, 100 divisions and 1,000 sections. [OCLC ResearchWorks - About DDC and the Summaries]

What has been noticed in a couple of places are the DDC RSS feeds.