Digital media such as Web sites, CD-ROMS, and DVD-ROMS all share similar functionality and content options. They run on a computer, and they allow your audience greater latitude than other media formats to create their own paths through your educational content.
Software called a Web browser allows you to view HTML pages. You can add additional media types and interactive functionalities to a Web page using software called a plug-in. The user may need to install the correct version of a plug-in in order to see such elements. Plug-ins are generally available for free and can be downloaded from the Web.
Plug-ins allow you to include many different elements on your Web site, including video, print layouts, and interactive or animated materials. They add useful functionality to your site, but you should check that the plug-in you require is readily available and will work across various types of computers. If you require too many, or uncommon, plug-ins, your audience may be unwilling to use your site.
If users will need a plug-in to access features on your Web site, make that clear on the home page or other pages where the plug-in is needed, and provide links to the sites where the plug-in is available for downloading. Provide an alternate version of a feature, such as a text- and image-only version, that will be accessible to people who can't use the plug-in version -- because of its larger download size, or because, in the case of visually impaired users, the plug-in version is not compatible with assistive technologies, such as screen readers. (To learn more about Web-accessibility issues, see the Making Media Accessible section of this guide.)
CD-ROMs and DVD-ROMs are compact discs that run on a computer drive. They can serve as "hard copy" distribution for your Web pages, allowing people to see your content (but not links to other sites on the Web), regardless of whether they have a reliable Internet connection. These discs may be especially useful if your digital content contains many large media files, such as digital video, which can be slow or difficult to download from the Internet.
CD-ROMs and DVD-ROMs can also be developed using computer languages or authoring tools other than HTML and plug-ins. You will need to work with a skilled computer programmer to produce these interactive media. Producing a CD-ROM or DVD-ROM follows much the same production process as producing a Web site, except that you need to schedule manufacturing and distribution of the final product.
Note that a DVD-ROM is different from a video DVD, which runs on a DVD player rather than a computer. You can add educational enhancements to a DVD of your video; these are described in the Video Formats section of this guide.