Universal Design for Web Applications

Chapter 3. Metadata

One person’s content is another person’s metadata.

—Stu Weibel

Among document formats, HTML is perhaps the most thoroughly researched with regard to accessibility. We know its strength is in its ability to express semantic meaning. In fact, most of HTML accessibility is about using semantics and structure correctly, enhancing them or working around their limitations.

When you look at your site, what do you see? Now load it in an older mobile device or mobile device emulator or a screen reader. Or find out what a search engine knows about it. The differences between your answer and theirs are the reason metadata is important.

What Is Metadata?

The typical definition of metadata is “data about data.” Samantha Starmer recently explained (http://tinyurl.com/6x5zve) how we use metadata to make decisions every day. What kind of food do you want for lunch? What color shirt do you want to wear today? As humans, we constantly identify properties of objects, create labels for the properties, then categorize the objects based on the labels—it is some of the first language that we learn (as shown in Figure 3-1): round, square, red, blue, tall, short.

Figure 3-1. A child’s shape sorter toy; http://flickr.com/photos/ellasdad/425813314/

Why is metadata so important on the Web? Tags, labels, document structure, and descriptions help us sift through the heaps of information ...