I see a few posts on this so far, but just adding another voice of feedback.
It's great to see what you're doing here. From a computer user side, the manga reader is quite functional. All it really feels like it is missing is a Table of Contents functionality, so that a user can leap between sections they're interested in, without having to scroll the whole way to page 100 to go see something there.
I'm sure there's a whole bunch of restrictions dealing with the content owners, but again, props here. It's nice to have some effort giving those of us who don't have any interest in gathering up print comics an option to just digitally grab at comics from anywhere that's not illegal.