Currently on the worldbuilding/outlining phase.

I’m using a customized self-hosted Semantic MediaWiki installation, and can’t imagine doing it any other way—it’s like Wikipedia with the added ability to aggregate and live-update information from related pages. For instance, I can create a story event page with the place, date, and list of characters involved—and just from that, each character’s page has a map of all the places they’ve been, a timeline of all the events they’ve been present at, and a list of all the characters they’ve met; and it all gets updated whenever I add or edit an event.

Plus it’s on a web server, so I can access it from any device with an internet connection.