If you're in the process of a redesign and are busy checking out the competition to ensure your newly retooled Web presence is in line with the competition, check out the WhatFont Tool.
The bookmarklet and Chrome Extension makes it easy to find out what fonts are being used in a webpage.
With the extension installed, by hovering over the font you like, you'll be able to see at a glance what web fonts are in place.
While you could use extensions like Firebug or Webkit Inspector to do the same, WhatFont is a far simpler, far more elegant solution.
A snapshot of the WhatFont tool is below. It's pretty fun to play with so check it out!