Google Inc., which bought YouTube last year for $1.76 billion is trying to earn back the purchase price and then some, is using an innovative advertising technique. This week, the video-sharing giant will begin hosting “semitransparent ‘overlay’ ads at the bottom of selected video clips. The ad disappears after about 10 seconds if the viewer does nothing; the featured clip automatically pauses if the viewer clicks on the overlay to launch the full pitch,” explained Yahoo news.