hmm.. i'll have to think about this when i have more time. one comment i have for now is that the words click on a user name to visit their profile/unsubscribe and seeing hsk beginner, etc, beneath that definitely made me pause and think user name wasn't the right word. but i see what you're doing..

another idea, instead of user name, what about show name - (user mike).. e.g.

HSK Beginner (user PopupChinese)

Chengyu Challenge (user Joe)

or

Joe - Chengyu Challenge, Word of the Day, more...

gotta run