Looks like a child of emacs org-mode and consumer-friendly google calendar. Sounds interesting, what sparked you to do it?
Seeing people adopt emacs, just for org was probably an inspiration. Jotting stuff down in free-form means people can build their todo-list structure to suit them so I'm hoping to see lots of cool things happening in the pages.
So far it's mostly techies that have come on board, hoping to get featured on Lifehacker or something where the true litmus test happens.