The use of multimedia shouldn't put an additional burden on teachers. Cost efficiency is important in terms of administration. You have to decide if it was really worth it.
Students get an immediate response.
It is possible to put together a combination of audio and text so that students can deal with the meaning. HyperCard and Designer's Edge were mentioned as useful authoring tools. Content has to be written in a form to fit multimedia with an understanding of the technical possibilities. Something must be designed for a specific environment. If you want to look at the Web only, look just at web materials.