MindMeister : MindMeister is an online mind mapping tool that lets you capture, develop and share ideas visually.
Mind42 : Collaborative mind mapping in your browser
Mockingbird : Mockingbird is an online tool that makes it easy for you to create, link together, preview, and share mockups of your website or application.
SQL Fiddle : A tool for easy online testing and sharing of database problems and their solutions.
RegExr : RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp).
