Over lunch I'm reading Carey Jewitt's 'Rethinking Assessment: Multimodality, literacy and computer mediated learning (2003). It's a really good (and relevant) read, even if the focus is upon high school study of a CD-Rom version of John Steinbeck's Of Mice and Men.
Using the celestial metaphor of stars within a constellation. The autor created the all the individual elements of the multimodal assignments. These might be images, sound clips, passages of written text, animation. These are the stars. They are projected onto the canvas by the author. The author intends to demonstrate his understanding or world view through this assesmblage of stars.
The reader has a gazes upon the different stars glistening on the black canvas overhead. She then follows her own path between the different stars, studying one element, then another and then another. She follows her own path between the stars. She might return to a star of pariticular interest. She might do this more than once for, having seen subsequent stars the first star might make more sense. She is making sense of the relationship between the elements. She tries to make sense of the the elements by making sense of the combined knowledge they project. She is intepreting meaning from the assemblage of image, text and sound. She attaches meaning to this constellation based upon the unique journey she followed between them.
The reader/astronomer has followed her own path, not a trajectory proposed by the author. She is not receiving the message transmitted by the stars (author), she is constructing meaning upon what has been projected onto the sky canvas. As such she is a producer - she is constructing information. She negotiates this meaning with the author.