Mind42 : Collaborative mind mapping in your browser
SQL Fiddle : A tool for easy online testing and sharing of database problems and their solutions.
metaflop : Metaflop is an easy to use web application for modulating your own fonts. Metaflop uses Metafont, which allows you to easily customize a font within t...
Etherpad is an Open Source online editor providing collaborative editing in really real-time powered by Node.js
