It woud be great to have keys into other databases from Wikidata. I'd be
happy to contribute Freebase IDs to matching Wikidata concepts.
However, I'm wondering if it really makes sense to have
a separate property for every type of ID. Shouldn't it be modeled more
like interwiki links so that each concept has many foreign keys each
with an associated data source. That's how we've modeled it in Freebase
and it scales quite well.
If I'm not mistaken this is what we plan to do. The current system we're using for the language links can certainly handle it, as it's not WP specific.
Cheers
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Jeroen De Dauw
http://www.bn2vs.comDon't panic. Don't be evil.
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