On 13.06.2012 18:04, Lydia Pintscher wrote:
Ok then let me define it more clearly. Wikidata's clear goal is to serve the Wikipedias. Use in other contexts will also be possible and encouraged but Wikipedia is the main target. It is for a project that values references for all the structured data and it is supposed to serve a multi-language audience. SMW is well established and used in professional and non-professional projects outside of Wikipedia. It usually serves smaller wikis and has quite some use in companies for their internal knowledge management. Obviously there is overlap but in the end the projects are distinct enough to co-exist just fine. Markus wrote a long email about this here: http://www.mail-archive.com/semediawiki-devel@lists.sourceforge.net/msg03369...
I'd like to expand on that a bit. Basically, the main difference to me is:
* SMW is for managing primary data, i.e. *facts*: "server X is located in room 123"
* Wikidata is for managing *claims* as we find them on Wikipedia: "according to report X published in 2005, the population of China in 2004 was 12345678, +/- 1000, including Taiwan"
So, Wikidata's data model is much more complex, and aimed at the type of information we typically see on Wikipedia. This allows is to provide extremely fine grained provenance data, but makes reasoning and querying a lot harder. It also means that mapping it to RDF is complex and awkward, not nearly as straight forward as it is with SMW.
So, if you are working with factual data and want to do complex queries, use SMW. If you have data which requires deep provenance information and are content with simple queries, use Wikidata (resp Wikibase).
However, we are working to make SMW and Wikibase (the Wikidata software) compatible where it makes sense: we want to share code for unit conversion, result formatting, etc. And I could imagine (but that's just a vague idea) that SMW one day could utilize our new method of storing structured data directly, without wikitext, but using it's own, simpler data model.
Anyway, keep in mind that Wikidata is build by the same people who initiated SMW! They are very well aware of the similarities and the differences. And we believe that the target audience for SMW and Wikidata *is* quite different.
-- daniel