Loads of HTML out there is unstyled, so you get a whole lot of 1990 in your browser. If you prefer it to be prettier, try this:
(function(){
var s = document.body.style;
s.maxWidth='660px';
s.margin='8px auto';
s.fontFamily='Source Sans Pro'; // adjust to your liking
s.fontSize='16px';
s.lineHeight='22px';
}())
Or as a bookmarklet: javascript:(function(){var s = document.body.style; s.maxWidth='660px'; s.margin='8px auto'; s.fontFamily='Source Sans Pro'; s.fontSize='16px'; s.lineHeight='22px';}()))"
.