All the favorites stuff is looking good, but I don’t think the user library filter needs a question mark… 
bucketed into swimlanes
I’m even learning new phrases in English here… 
OT
You mentioned SEO keywords recently, and it occured to me that when I’ve been searching for books I’d use phrases like:
- Korean book recommendations
- easy Korean [children’s] books/novels
- Korean books/novels for beginners
It wouldn’t have occurred to me to search for a “difficulty list”, but I suppose with Japanese being more popular it’s not surprising Japanese language learners might expect those kinds of resources.
I don’t know if that’s helpful or not, just a small observation. 
Looking forward to the book providers update! 
