I’m not too big on installing browser extensions, but WhatFont is one I’m extremely happy I came across. No more having to snoop through source codes to see which font(s) a website is using. WhatFont does everything for you!

As you can see in the screenshot above, it also gives you the font size, colour, and line height used for the text/image you selected. And best of all, it also now supports Typekit and Google Font API.

Get it in the Chrome Web Store for free.