ScreenCaptureSyphon

ScreenCaptureSyphon shares a whole or a part of your screen or of a window as Syphon, and sends it to another application as video.

PowerPoint, Keynote, as well as materials on browsers - such as Flash contents (YouTube, etc.), site contents, etc., in WebGL - can be shared as Syphon. Not to mention that TCPSyphon allows users to transfer data with less delay to another machine.