Item [8] was mentioned in this talk: http://www.youtube.com/watch?v=3kEfedtQVOY by Meredith Patterson. She contends, and it seems sound to me, that the time has passed to be "tolerant when accepting," and that you should instead only accept regular grammars or, at worst, context-free grammars as input languages on the open Web.
Scalability - Nothing you can do will work in scale. You always need to build for now, and the near future. When you have to scale from 5 to 10 to 100, you can try to plan for everything, but you'll see that things that you didn't think will go wrong will, and vice-versa. Don't plan for massive scale, build for now + the near future, and reiterate when needed.
From a UX perspective I would increase the font-size a little bit. Just makes it easier to read.