Synapse VS matrix-doc

Why not Matrix? Here's one reason: it has incredibly hard-to-debug edge cases, and plenty of bugs. One of my favourites is the one where people are kicked out of your room at random, which was reported a year ago[0]. It wasn't fixed, however, because the head of the Matrix foundation (Matthew) presumably didn't like the issue being posted on Twitter.

This is honestly really disappointing behaviour from a platform owner.

[0]: https://github.com/matrix-org/synapse/issues/14481

Synapse

The permanence is a difficult issue, there are some description here and here, and some proposed solutions here and here , but the main point is that in a federated system you can not be sure about that the others will work in a good faith. If you have shared or sent something to someone outside the infrastructure you control, you can not reverse that. Like if you have sent an email from protonmail to a gmail address, you can not force google to delete that.

Discord? There are many options, but Mattermost is probably the most Discord like. You might choose Matrix instead if you want something federated like the other platforms I've linked here.

Meh.

Group voice and video calls are not E2EE, and use Jitsi, but this is expected to change with Native Group VoIP Signalling.

DMs in Matrix are always E2EE, and MSC3401: Native Group VoIP Signalling means there should be E2EE in group calls.

From my perspective, the really exciting thing about this that it works equally well in mobile web browsers as well as desktop web - clicking on a link on Mobile Safari should Do The Right Thing without having to install anything.

Moreover, because it's built on Matrix, MSC3401 (https://github.com/matrix-org/matrix-doc/blob/matthew/group-...) means that we'll finally have decentralised cascading video/voice conferences once the SFU (selective forwarding unit) component is added into the mix. So, for instance, users on the same homeserver will get their video feeds relayed locally with minimal latency... and then users on another remote homeserver will also get mixed locally with minimal latency, trunking the two together. If the link dies or one homeserver dies, the conference will keep going - i.e. precisely the same semantics as normal Matrix.

What metadata does Matrix protect? Encrypted state events still aren't a thing for example https://github.com/matrix-org/matrix-doc/pull/3414 This means that server admins know what groups a given account is a member of, private or not, and they also have a general idea of what the topic of said groups are, even if they're encrypted. This would be a problem for groups about sensitive personal medical issues, like a private HIV survivors or Alcoholics Anonymous group.

The protocol itself is flexible and can be changed through spec change proposals on their Github. They're currently working on implementing threads, and they recently implemented spaces, which functionally combine the concept of Discord servers and server folders. They can also be nested.

Something we're trying to do about this on the Matrix side is MSC2716 (https://github.com/matrix-org/matrix-doc/blob/matthew/msc271...) - the ability to import archives of existing content into Matrix, and thus 'lock it open' and decentralise it for posterity: as long as one of the servers participating in that room stays alive (and the room is set up with infinite data retention, obviously) then the conversation will live on forever. (That MSC is also well worth a look for those interested in how Matrix works under the hood; MSC2716 was a surprisingly tricky problem to solve but it's basically finished now!).

Our first step will be to import all of Gitter's archives into Matrix - but we're then planning to add MSC2716 to all the existing Matrix bridges so that folks can use it to liberate chat history from Discord and Slack if desired, and avoid it getting paywalled/siloed/lost/held-hostage forever. We're also expecting to do USENET, mailing lists, forums, public IRC channels which have explicitly opted into logging... and generally archive as much possible in an open decentralised fashion, and ensure that gatekeepers can't lock up and blackhole info going forwards. After all, information longs to be free :)

This is an accident of history and will eventually be corrected: https://github.com/matrix-org/matrix-doc/issues/2678.

It is certainly not intended that new features are unencrypted, but unfortunately sometimes it happens in order for features to get added sooner.

On the Matrix side we've been keeping a close eye on JMAP, which operates in a fairly similar space to our new 'sliding sync' protocol (https://github.com/matrix-org/matrix-doc/blob/kegan/sync-v3/...). We would love to adopt JSCalendar & JSContact in Matrix if they are good to go :)