Plone
Obsidian provide custom built web applications using the Plone Content Management System, including Obsidian's SLATE Conference Management System.
Plone is a powerful, flexible Content Management Solution that lets non-technical people create and maintain information for a public website or an intranet using only a web browser. Plone is easy to understand and use — allowing users to be productive in just half an hour — yet offers a wealth of community-developed add-ons and extensibility to keep meeting your needs for years to come. Blending the creativity and speed of open source with a technologically advanced Python back-end, Plone offers superior security without sacrificing power or extensibility PLONE