Anyway, I agree. Text should always have a max width. Long lines of text aren't really readable.

I use this in my SurfingKeys settings, and use it on a lot of sites to make them more readable:

  mapkey('<Ctrl-m>', 'Centers the current page', function() {
    document.body.style.cssText = "font-family: sans-serif !important";
    document.body.style.cssText += "color: black !important";
    document.body.style.cssText += "line-height: 1.4 !important";
    document.body.style.cssText += "margin: 0 auto !important";
    document.body.style.cssText += "max-width: 60em !important";
    document.body.style.cssText += "background: none !important";
    document.body.style.cssText += "background-color: #FEFEFE !important";
    
    return true;
  });