When visiting any URLs that have been (publicly) targeted by Prism, a small notification will appear alerting that this site is being surveilled. You will then be presented with an ethereal Pink Floyd track from the "Dark Side of the Moon" album.

http://projects.justinblinder.com/Dark-side-of-the-Prism

For the addon: https://addons.mozilla.org/en-US/firefox/addon/dark-side-of-the-prism/

 

 - Yep us too. Apparently the PRISM program has been monitoring The Galactic Press as well.