To facilitate exploration of the massive amount of digital information, new ways of content representation are required. This article presents several examples and prototype systems that show how information visualization techniques can be applied for content representation. Through the power of information visualization, visual content maps can be created automatically.  These maps extract and define information patterns, categories, and relationships among authors, concepts, or other information entities.  The maps also support various interactive functions for the users to explore concept relationships and the underlying information. The paper also raises many questions related to content measurement, content structures, and visual displays of content and content structures. It is believed that understanding these issues will represent a significant step toward semantic maps for information access.