The app is a simple microphone muter. It sits in the menu bar, you get to switch between two modes: push-to-silence and push-to-talk. Once you pick the mode, you can use a hotkey (mine is fn-key) to toggle microphone off or on respectively.
So if I ever need to sneeze or cough, or similar during next episode of The Context, no one will hear it because of the app.
Incidentally the Squarespace note app may be the fastest and most convenient way to post to Tumblr. Just FYI