First let us consider the production of digital magazines. As we all know digital magazines try to mimic the look and feel of print magazines. So they provide two up views, nice animation of page turning, but as the resolution of most computer monitors is poor, they provide zoom levels of one or two, which may not be sufficient. One new vendor (Example: Digital DNA epaper) has come up with a feature where the selected article is provided in HTML, where the text size would be much easier to read.
As a second example, let us consider the publishing of podcasts. If this is just an audio file, it needs to be downloaded and played. Alternatively it can be streamed. As our rate of reading is much faster than our rate of listening and also provides opportunities for skipping content, providing a transcript of audio would benefit customer a lot. (Ex:Steven Cherry's Computing podcast on IEEE Spectrum) It is also helpful if the accent of the presenter is not familiar to the customer.
As a third example, let us see how the audiovisual recording of conference sessions are being served. Most of these are just served as streaming video files, may be some times with timeline table of contents. The presentation slides used by the speaker usually are not mixed or provided with the video. This product will delight the customer, when customer can access the content in different ways like read the slides, read the transcript, listen to only audio and view the video recording. (Example: GUADEC 2013 Conf sessions by SuperLectures)
While providing the multimodal features is a challenge because of the additional effort needed, there will be significant benefits in terms of attracting more customers. Not only that, providing the contents in multiple formats particularly text formats also helps the content accessible to search engines and thereby increase their accessibility.