[ZoFreX]

I can't type underscore on my "British" layout MBP keyboard.

I wrote a typing tutor a while ago and this is a somewhat common pitfall, to manually handle characters by pulling key codes. Instead you should let the O/S tell you which character was typed (and also check key codes, for things like backspace) which then handles different layouts / locales etc.

Edit: Ok, it works in Chrome - so it's not working for me in Firefox 14.0.1 on OS X Lion.

Now that I can use it, I love it, but I have one request - I'd like to be able to go back and see my stats, please!