hackmd.io vs Notion

Allows multiple people to edit the same note in realtime.

Automatically generates a "table of content" of your headlines.

Allows you to go back in time to a previous version of your document.

Note: Enterprise Edition has even more refined permissions, but the permissions in the non-enterprise edition are pretty powerful.

This is truly helpful for organizing your documents.

Supports creating slide-shows in markdown.

It's multi-platform (works well on smartphones) and there is no need to install anything.

Use LaTeX seamlessly within the editor.

Perfect for working at night.

This is really helpful for longer documents. Or even "books." This is also super helpful for journaling activities and the like.

HackMD service can be downloaded and installed in custom servers.

Is available as desktop app.

Adds supports for embeddings from Youtube, Vimeo, Speakerdeck, GitHub gist etc; and even creating UML diagrams, Graphviz graphs, Timing charts, and even Music notes! and alerts and comments boxes and emojis.

HackMD Core's source is available on GitHub.

You can subscribe to it for more features.

People who subscribe can push and pull unlimited.

Even the right-click menus on the web are the same as the app.

One of the most complete applications one can use to build a personal dashboard (or professional) and migrate all other services to it. No more calendar, task, notes, financials, lists, writing and wiki apps, just Notion.

You can have a ridiculous amount of information within a single note. Look at how it works, you'll be surprised!

You can upload files and embed online stuff in any hierarchical structure using pages, toggle lists, etc.

This feature makes it very easy to find certain notes and such. And great for visual people as well. You could also add images as icons instead, if you like.

The basic unit of organization in Notion is the block, which can be a chunk of text, an image, a bullet point, or even a link to another page. Each page consists of these blocks, which can be easily reorganized, moved to other pages, converted into other content types, or generally manipulated in many useful ways. Because of blocks, restructuring information in Notion is way easier than in any other wiki or notebook app.

To-dos in Notion aren't just dot point lists. You can drag and drop them into columns just like Trello (Kanban style), you can have sub-tasks, and you can easily mark things off as completed so they are no longer in your way. Notes are also powerful, with proper formatting and ways to manage and search for them, which makes it a great Evernote alternative.

Works with Android, iOS, Windows, & Mac OSX.

You can easily start writing a bunch of web pages, share it with co-workers and choose whether to publicize or keep your contents private. It's also easy to hyperlink pages.

You can create different views for a page's content and easily toggle between kanban, table, etc. (As long as the content is able to allow different views.)

Just type in a word and you'll have results in no time at all.

You can attach files in table cells, which is a feature missing in most spreadsheet-like applications.

You can use calculation/formula, links, attachment, inter-referencing of data from other pages or tables, embed documents and images in the table cells.

Add code blocks, Headers, bullet point, numbered lists, or To-Do boxes by typing using Markdown Syntax (instead of klunkily moving the mouse to formatting boxes)

Lets you restore your page to a past edit. Also works with sub-pages and databases. Though it is worth mentioning that it's a paid feature.