1 Document structure and metadata

Content developers should use structural markup and use it according to
specification. Structural elements and attribute (refer to the index of HTML elements and attributes to identify them)
promote consistency in documents and supply information to other tools (e.g.,
indexing tools, search engines, programs that extract tables to databases,
navigation tools that use heading elements, and automatic translation software
that translates text from one language into another.

1.1 Metadata

Checkpoints in this section:

• 13.2 Provide metadata to add semantic information to pages
  and sites. [Priority 2]

Some structural elements provide information about the document itself. This
is called "metadata" about the document -- metadata is information about data.
Well-crafted metadata can provide important orientation information to users.
HTML elements that provide useful information about a document include:

1.1.1 TITLE: The document
title.

Note that the (mandatory) TITLE element, which only appears once in a
document, is different from the "title" attribute,
which applies to almost every HTML 4.01 element. Content developers should use
the "title" attribute in accordance with the HTML 4.01 specification. For
example, "title" should be used with links to provide information about the
target of the link.