Systems and techniques are disclosed for enabling structured data to be associated with visual content in a manner that preserves the ability to edit the visual content using a content application such as a notebook application. Techniques and systems enable semantic notation to be introduced into selected regions of the visual content that indicate the visual content's structured data, allowing the content to be searched and accessed more easily by common search technologies and search engines. The semantic notation is assigned to the visual content so that the introduction of the semantic notation does not hinder the user's viewing or editing of the visual content with a content application. The inclusion of the semantic notation does not cause existing visual editing tools that do not understand the semantic notation to cease to function properly.