Structured Data Markup Helper shows you how to update your site so that Google—and potentially other companies' products—can understand the data it contains. Once Google understands the data on your site, your data can be presented more attractively and in new ways. In addition if you send HTML-formatted email to your customers, Markup Helper can show you how to change your email templates so GMail can present the data in your email in new and useful ways. Markup Helper ignores any existing markup in the example page or email that you tag. So if you tag some text that is already identified by markup, Markup Helper will go ahead and add additional markup for the tag. When needed, Markup Helper will wrap your tagged text in a element and add microdata to the span. If adding a span element would break the DOM, Markup Helper will add microdata to the page's element.