bubbl.us is a mind map tool. It's a visual thinking tool for structuring information, helping you to better understand, remember and generate new ideas.
License: Free
Bubbl.us offers a straightforward interface and is great for basic mind mapping, while MindMeister provides a more robust set of features, including real-time collaboration and versatile export options. MindMeister is better suited for teams and more complex projects, whereas Bubbl.us is ideal for individual use or simple brainstorming sessions.