While the technology is generally called green screening by most people, it is actually called chroma keying and it can be ...

(2) A computer terminal that displays green characters on a dark background. Widely used in ... the character-based green screen gave way to the graphics-based interfaces of Windows and Mac.

Depending on your setup, a green screen could be among the best gear for streaming. A good one will also do far more than offer a colored background to superimpose your surroundings, too.