I am wondering what languages Duolingo has bonus Skills for. I see them for Spanish but not Dutch. Why?
The original (pre-incubator) languages to/from English have the usual three.
English for Chinese speakers has Chinese New Year. Not sure about the other courses for Chinese speakers.
Japanese for English speakers was planned to have three: National Holidays, Olympics, and Subculture. Not sure if all if them were produced.
I've seen references to Norwegian having some.
Why no more? Check the last paragraph here: http://duolingo.wikia.com/wiki/Lingot_store/Bonus_skill