From main web page
What is TreeLine?
Do you have lots of sticky notes lying around with various useful information jotted down? Or many lists of books, movies, website logins, personal contacts, or things to do? Can you find them when you need them? Well, I often couldn’t. So here’s my answer.
Some would call TreeLine an Outliner, others would call it a PIM. Basically, it just stores almost any kind of information. A tree structure makes it easy to keep things organized. And each node in the tree can contain several fields, forming a mini-database. The output format for each node can be defined, and the output can be shown on the screen, printed, or exported to html.
A source code repository is available at GitHub.
There is a low-volume email list for users to discuss TreeLine. To subscribe, go to this page.
It is interesting to know, it is offline, portable, extensible, and can be installed on Linux, Windows and Mac OS. It is open source and free!
NOTE: I shared TeeLine here for note takers and to see what we can learn from it for our Tiddlywiki!