13.1 billion triples
Here is the break-down of such an estimation:
- MySpace: 250 million people * 50 triples (in average) = 12.5 billion triples ;
- AudioScrobbler: 1.5 million users (only Europe?) * 400 triples = 600 million ;
- Jamendo: 1.1 million triples + 5000 links to other data sources ;
- Magnatune: 322 000 triples + 233 links ;
- BBC John Peel sessions: 277 000 triples + 2100 links ;
- Chord URI service: I don't count it, as it is potentially infinite (the RDF descriptions are generated from the chord symbol in the URI).
Now, I wish linked data could be provided directly by the data sources themselves :-) (Again, all the code used to run the DBTune services is available in the motools project on Sourceforge).