Haven't found the one yet:
Optional but really ideal:
  • can delete messages from the device of the person you sent it to, no matter how old
  • decentralized, your username is a public key
The state of messaging is ridiculous as of 2020.
Discord (software) by Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli's discord ID: cirosantilli#8921. See also: how to contact Ciro Santilli.
You gotta be born after the year 2000 to understand it.
This is becoming more and more popular as a group chat with channels and threads possibility as of 2020.
Very similar to Slack.
Not possible to anonymously join just one server without creating a new account? What's the point of servers then! www.reddit.com/r/discordapp/comments/6gmjl7/changing_nick_before_joining_a_new_server/ Oh, also nicks don't hide your username from the server in any way, you can get the original username by just clicking on the person's username.
No proper threaded discussion without creating new channels? As of 2022 there is kind of a way, but it was a bit obtuse.
As of 2022 they also have a school hub: support.discord.com/hc/en-us/articles/4406046651927-Discord-Student-Hubs-FAQ which auto creates groups by university email access. Good idea, and shows popularity amongst that user group.
Discord is useless if you want to participate in more than one large group because of this. It is impossible to get email notification for selected threads you care about.
Jami (software) by Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli worked on it for a brief time in 2016, when it was still called Ring, before he got fired. :-)
The people were quite nice and the project idea is fine, Ciro hopes they succeed.
Video 1.
Ring - Peer to peer network for real time communication - FOSDEM 2016 by Ciro Santilli
. Source.
Jitsi by Ciro Santilli 37 Updated 2025-07-16
As of 2020: end-to-end encryption optional and turned off as default, and marked as experimental...
WhatsApp by Ciro Santilli 37 Updated 2025-07-16
Video 1.
WhatsApp founder Jan Koum talks about their Journey by Roots (2017)
Source. Good talk, explains how everything happened in the perfect location at the perfect time: unemployed people who knew how to code, bought an iPhone, the next big platform, at its very beginning, they had just release the required push notifications API, and he travelled a lot and knew how much SMS sucked, especially international.
Obviously with the single intention of killing a competitor.
It is impossible to make money off WhatsApp as it is because of end-to-end encryption.
Facebook just clearly bought it to prevent it from actually growing further and killing facebook.
It is mindblowing that the sale wasn't cancelled due to anti trust.
The outcome of this is that WhatApp will remain with the same feature set forever, while other competitors have been growing, notably Discord and Slack.
Your profile picture, name and status are public by default as of 2022!!! OMG!!!
This means that all secret services in the world have alrady scraped this information for everyone that uses WhatsApp!!!
They just have to go incrementally through the list of all phone numbers... 001 0000 0000, 001 0000 0001, 001 0000 0002, etc. and then you can deduce who has which phone number.
OMG... it is analogous to the Facebook profile face dump.
FFmpeg by Ciro Santilli 37 Updated 2025-07-16
FFmpeg is the assembler of audio and video.
As a result, Ciro Santilli who likes "lower level stuff", has had many many hours if image manipulation fun with this software, see e.g.:
As older Ciro grows, the more he notices that FFmpeg can do basically any lower level audio video task. It is just an amazing piece of software, the immediate go-to for any low level operation.
FFmpeg was created by Fabrice Bellard, which Ciro deeply respects.
Resize a video: superuser.com/questions/624563/how-to-resize-a-video-to-make-it-smaller-with-ffmpeg:
ffmpeg -i input.avi -filter:v scale=720:-1 -c:a copy output.mkv
Unlike every other convention under the sun, the height in scale is the first number.
ffplay by Ciro Santilli 37 Updated 2025-07-16
Awesome tool to view quick stuff quickly without generating files. Unfortunately it doesn't support all options that the ffmpeg CLI supports, e.g. ffplay multiple input files. One day, one day.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact