You can use thinktype for almost any purpose with the right conventions. For example, to use it as a todo app, just use the "TODO" keyword in notes, and you'll find them when you
To use it as a shopping list, write something like "TODO: Buy ..." and search for "todo buy" when you go shopping.
Working towards a launch? Write notes like "project TODO mvp", to be able to search for everything you need to do to have a minimum viable product.
Once you have done a task, replace "TODO" with "DONE". This lets you search for all your achievements.
ThinkType has two sort modes. By default, search results get sorted by match, but you can also sort by priority/recency, which is especially useful if you use it as a todo app like described above. You can toggle between search modes with a button or a keyboard shortcut (Ctrl+#).