Some of you out there may be too young to remember the venerable VU meter (or generation loss, or any of those other "charming" frustrations inherent in analog production technology). But with the advent of digital, well, everything, new meters, and more importantly, new practices had to be applied in their usage.
The fine folks over at Dorrough Electronics have put together a short video demonstration on how to effectively read these newer audio meters. In it, they give a quick overview of the meter's history, along with a live demonstration in a post audio context.
From the beginning of electrical audio signals and the telephone industry's first meters through the broadcast and motion picture eras, the evolution of audio monitoring standards are presented in this interesting historical chronicle.
There is a low quality version, split into two parts, along with a high quality single clip.
Link to multimedia page, via dorrough.com.