The Scalable HTML Content feature makes the published movie scalable, so it fits the screen it is viewed on (even as the screen is resized!).
For example, say you shoot and publish your movie at a size of 1024 pixels, but the movie is viewed on a website where the maximal resolution can only be 800 pixels. In such a case, the Scalable HTML Content feature scales the movie down to 800 pixels so that it fits in the available space.
This approach is quick and easy to implement, but it has a major flaw: you lose control over how your content will actually be experienced. Only the learners who have exactly the same size screen as yours will see the course as you designed it. The other learners will see the course either bigger (which means possibly pixelated) or smaller (which probably means too small to be comfortable).
This option will be covered in Chapter 15, Finishing Touches and Publishing.