For WCAG validation it is important to add semantic information to data tables. They are used throughout Drupal, but is most important for Views.
Some information about the process for creating good tables is in:
Taking from the WebAim description:
"The purpose of data tables is to present information in a grid, or matrix, and to have column or rows that show the meaning of the information in the grid. When screen readers read straight through data tables—especially large ones—it's easy for users to get lost.
In order for a data table to be accessible, it must have the proper markup in the HTML. When the proper HTML markup is in place, users of screen readers can navigate through data tables one cell at a time, and they will hear the column and row headers spoken to them."
PASSED: [[SimpleTest]]: [MySQL] 57,465 pass(es). View
PASSED: [[SimpleTest]]: [MySQL] 56,910 pass(es). View
FAILED: [[SimpleTest]]: [MySQL] Unable to apply patch drupal-864006-67.patch. Unable to apply patch. See the log in the details link for more information. View