Acoustic treatments

[QwertyAccess]

http://www.engadget.com/2006/04/04/how-to-theater-or-studio-acoustic-treatments/
Anyone have any comments on how effective this idea is?, it looks a bit interesting, though at the same time seems like it wouldnt really do anything... (though it would be nice if i can hang something like this infrotn of my window (my entire wall is a window), so i can eliminate some sound exiting my house.

Oh, and oh my god at the first comment on that page...

[Zilch]

The comments contain the best information. Following some of the links there, I came upon this primer on room acoustics:

http://www.ethanwiner.com/acoustics.html

Again, this via Steve Schell for the material performance specs:

http://www.bobgolds.com/AbsorptionCoefficients.htm