One of the major use cases we have for Wikidata (next to providing general purpose data about the world and acting as a hub that connects many different databases) is concept tagging. So far not much has happened in that space it seems compared to the other two. Just recently I came across a tweet talking about the use of Wikidata for exactly that at the Finnish Broadcasting Company and I asked for some more details. Micke has now written down what they're doing and how they did it in a blog post: http://wikimedia.fi/2016/04/15/yle-3-wikidata/ Great use of Wikidata's concepts and stable IDs.

Cheers
Lydia