@orci Well, not really a journal, but journaling is one of the things it does. #TiddlyWiki saves everything to a single HTML file. How you handle that file is up to you. You can use an encrypted sync service and your choice of cloud storage to keep your desktop and phone synced. You can also host your wiki on a public server (that's a big no for me).
I keep all my ideas, half-done projects, and meeting notes in it.
Lots of plugins for looks and functionality so you can make it how you want it.