什么情况下需要用Normalize.css 或者 Reset CSS?

为什么用chrome的时候没有看到stackoverflow站点使用类似的重置css，是需要兼容低版本的浏览器才需要使用类似的样式进行统一重置吗？
Normalize的说明：
What does it do?

Preserves useful defaults, unlike many CSS resets.
Normalizes styles for a wide range of elements.
Corrects bugs and common browser inconsistencies.
Improves usability with subtle improvements.
Explains what code does using detailed comments.

Browser support

Google Chrome (latest)
Mozilla Firefox (latest)
Mozilla Firefox 4
Opera (latest)
Apple Safari 6+
Internet Explorer 8+