Orbitalwarehouse uses many great open source components, here are some of the major ones:
The very excellent Raphaeljs is used to render the SVG workspace.
Orbital WareHouse uses Nginx with PHP-fpm.
All data is backed into a Postgresql 9.1 database. Postgresql provides full text indexing for search facilities.
All servers are running Ubuntu Linux.
Etherpad Lite does awesome collaborative editing.
Twitter Bootstap makes responsive design 1000% easier: