Is there any significance to the dimmed text in Safari 6?
The point of this is to make the domain of the site you're visiting blatantly obvious. Many phishing scams will use URLs that look very similar, but not exactly identical to the site they're trying to mimic (using things like, for example, paypal.com.mysupersketchydomain.ru), and this technique (now used in most modern browsers) helps to mitigate that risk even for non-tech-savvy users.