HN Feature request: todo list/project collaboration

With a little more effort HN could be turned into a hierarchical todo list or project organizer. It would help me a lot in organizing my daily tasks and projects (provided I could keep a couple of pages private or share a couple pages with my team via invite). If the owner doesn't have the time he/she could either opensource the codebase or sell people a version for self hosting. btw what is it written in ?