Ooh, I used to use Duolingo for Spanish vocabulary but never found it very useful. I imagine it would work a lot better for dipping one's toes into a new language, though (I'd been learning Spanish in school for a few years).

I know almost nothing about Norwegian -- how are you finding it? Is the grammar difficult? I've always had a vague admiration for the Scandinavian languages (Finnish looks quite pretty written down with all those vowels) but never actually considered learning any.