It was a nice read, and I like the way the idea was presented. But one thing that stood out to me as kind of odd was the distinction between typing lowercase and uppercase characters. Automatically assuming lowercase to be a "keyword" does not seem like the right idea to me. Most sentences on the web might start with a capital, but not all of them will do. (For example here on HN, you have in the nav bar "new | threads | comments | .." None of them starting with a capital.