As an argument to stress the importance of the Semantic Web and as example data to evaluate tools it would be nice to have a library of real world RDF-S/OWL instance data available. My impression is, that there are many schemas around, but it's harder to find real life instance data. This might be due to copyright issues or the fact, that the borderline between classes/schema and instances/data is not always clearly marked and some projects rather use a representation as classes than a representation as instance data.
So, if you know of RDF-S/OWL instance data which is publicly available and shows an interesting application please let us know. I'm especially, interested in the impact of its usage. ;-)
The following is interesting Semantic Web data I know of:
* Wordnet - a lexical database for the English language 
* UNSPSC (Universal Standard Products and Services Classification) representation as classes 
* Wikipedia in RDF 
* Open Directory DMOZ in RDF 
* Open Bio-Medical Ontologies in OWL (rep. as classes) 
* FOAF - Friend of a Friend (many small instances available on the Web) 
I will summarize all statements and post it to the list again and maybe create some wikipage for persistent reference.