@baars - thanks a lot and glad you like it! can you confirm that clicking to edit your username didn't work on the profile page? This sounds like either a bug or a usability problem. Did you hit "enter" to submit the entry after changing it?

And thanks for the positive feedback. We're experimenting with everything from podcast structure to HSK question types (there are four major ones on the standardized exam) and will be rolling out a variety of different types of content over the next few weeks. Very much a learning experience for us too.

I'm convinced testing is a great way to learn when done right, and the HSK is a good test for learning. It tries to catch you on a lot of small things no-one would ever really bother to correct you on (see 快 versus 锐) as an adjective for knives, but that makes a huge difference in how others perceive your fluency.