I want to record audio and video from my screen with Camstudio. This requires the use of the "stereo mix" or "what you hear" devices, which are apparently normally disabled in Windows Vista/7/8. Installing Virtual Audio Streaming creates a new playback and recording device inside the Sound configuration which serve the same purpose as "stereo mix." Using those devices, I can record audio.

One more thing: It says that the trial version will add noise to the audio. I honestly don't hear it. Not sure what's up with that... maybe it will show up after a trial period of time? I wish the developer were a little more clear on the limitations of the trial version.