TakeNote is described as 'was made by developers for developers - a simple, plain-text note-taking app for the web with Markdown support. What you see is what you paste. No WYSIWIG, no formatting pasted from the web, and no features you don't need or want' and is a Note-taking tool in the office & productivity category. There are more than 100 alternatives to TakeNote for a variety of platforms, including Windows, Mac, Linux, Android and iPhone. The best alternative is Joplin. It's not free, so if you're looking for a free alternative, you could try Standard Notes or Google Keep. Other great apps like TakeNote are Notion, Microsoft OneNote, Simplenote and CherryTree.
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.