Scapple!

Lucidchart is an online diagram and flowchart software that supports Microsoft Office Visio import and can work on any operating system. The easiest way to draw flowcharts, wireframes, UML diagrams, network diagrams, mind maps, iPhone mockups, site maps and more. Work together in real time with your team and clients! Along with the online version, Lucidchart also has a downloadable solution that runs on Mac, Windows and Linux; this enables offline editing at any time! »

Pencil is a standalone app or Firefox extension that lets you create diagrams or UI mockups. It doesn't have collaboration/multi-user features.

FreeMind is a premier free mind-mapping software written in Java. The recent development has hopefully turned it into high productivity tool. We are proud that the operation and navigation of FreeMind is faster than that of MindManager because of one-click "fold / unfold" and "follow link" operations.

Lucidchart is an online diagram and flowchart software that supports Microsoft Office Visio import and can work on any operating system. The easiest way to draw flowcharts, wireframes, UML diagrams, network diagrams, mind maps, iPhone mockups, site maps and more. Work together in real time with your team and clients! Along with the online version, Lucidchart also has a downloadable solution that runs on Mac, Windows and Linux; this enables offline editing at any time! »

Freeplane is a powerful and free software for building mind maps. It is a redesigned version of the well known FreeMind , and is created by one of FreeMind's key developers. The software is written in Java, and supports any platform capable of running current versions of Java.

Mindomo is the easiest online software for creating mind maps, concept maps, outlines and various other types of diagrams. The following features make it the perfect choice both for business and education:* real-time collaboration* you can work on maps even if your internet connection is down, and your changes will be automatically synchronized when the connection is restored* playback mode that shows you how a map was built* maps can be turned into presentations or real-time editable outlines* Google Apps and various LTI integrations (Canvas, Moodle, Blackboard, Desire2Learn, itslearning)* great variety of exports (PDF, RTF, PPT, TXT, OPML, MPX, HTML, ZIP, PNG, XLS, MOM, MM, MMAP)* Google Drive, Dropbox, FTP and ZIP backups »

SimpleMind is a great Mind Mapper with focus on simplicity and ease of use. Multiplatform, with live mindmap transfer.

VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts. Such maps can help you to improve your creativity and effectivity. You can use them for time management, to organize tasks, to get an overview over complex contexts, to sort your ideas etc.

SpiderScribe.net is an easier and more flexible way to create mind maps and brainstorm online. It allows to connect notes, images, files, etc. into free form maps.

Big Hairy Goal is an easy-to-use tool for getting your ideas down and to arrange them in a way that gives you more insight. The approach is much like mind mapping but can be non linear. It's more like a whiteboard you attach note cards to and connect them with lines or reorder them. Big Hairy Goal automatically moves cards aside if you insert a new one somewhere. So when your paper notes ever required a total rewrite because things have gotten too crowded and no space is left to add new notes, you can imagine what Big Hairy Goal does. »

Popplet is a platform for your ideas.