An annotation and markup tool is a text or drawing tool that allows you to add information to text, images, databases, or other content. These tools can also be used to annotate content in multiple formats, such as a whiteboard or a PowerPoint presentation. Annotation and markup tools help with visualizing data, recording transcriptions, creating images, and more. These tools also have some nifty features that make it easy to take notes during screencasts. Since it's become so popular, there is a big demand for tools and plugins to help people integrate annotation into their websites/apps or to improve the user experience of existing annotations.