At the core of most web pages are two elements: content and presentation. Content is the concept, idea or information that needs to be conveyed. One may say “content” is the “what”. Presentation, on the other hand, is the “how”.
Let’s think about an example of a recipe. The content of a recipe include the identification of ingredients, and the instructions to use the ingredients to make a dish. At the most abstract level, this portion is not even language dependent. The fruit “apple” is only called “apple” in English, but it is represented by a different name in a different language!
The presentation of a recipe is how the information is presented. If the recipe is broadcasted on radio, then the presentation is completely audio. If the recipe is written in plain text (perhaps as a part of an email message), then the presentation is textual. If the recipe is illustrated in a cook book by pictures, then the presentation is photographic. Last, but not least, if the recipe is shown in a video clip, then the presentation is multimedia.
Note that even in text form, there are many presentation styles to choose from. A recipe can be described in paragraphs, in bullet point outline style, or in a table.
The importance of this section is the separation of content from presentation. While there are certain types of content that inherently limit the choices of presentation, most types of content has a wide variety of viable presentations.