The name “HackMD” doesn’t do this concept justice, nor do the more common descriptions of “shared notes” or “collaborative document”. It is a full replacement for chat: perhaps it could be called random access chat or parallel 2D chat ?

HackMD itself is a web service for collaborative documents in Markdown. This isn’t special to HackMD, but we have used it for its scalability, markdown support, and privacy in the “view” mode.

Primary articles


  • Synchronous questions, no disadvantage for quiet people.

  • Anonymous questions.

  • Parallel answers by a large number of helpers.

  • Easier to go back and review past questions during Q&A sessions (compared to scrolling through chat), for example finding important or unanswered questions.

  • The above can make a course feel much more interactive than it would otherwise.


  • Overwhelming flood of information

    • But you wanted more interaction, right?

    • Co-teaching helps here, one person can focus on watching.

    • Students must be warned to be deliberate about where they focus their attention (different learners have different interests).

  • It is another tool to use

    • Not required for basic learners, learners can begin using when they are comfortable.



  • Actively use HackMD during this course.

  • Observe how the instructors integrate it during the course itself, and can immediately respond to the questions.

  • Observe how instructors occasionally mention and screenshare HackMD to validate to the audience that it is being watched.

  • Keep HackMD open. Can you balance it and watching. Does it increase or decrease engagement?