Milkr is a collaborative mind mapping tool that can be used to share thoughts and organize information. Users can create spider diagrams containing as many interconnected notes as they wish. Notes can be re-arranged in a drag-and-drop interface. The content of each note is edited with Markdown. Notes may also have attached files and images, inline images, embedded YouTube videos, and more. Other users can also attach comments to individual notes within a diagram. A number of sample diagrams are presented at the bottom of the Milkr home page. Milkr works in any modern browser.