Thanks! I did not know or remember Wikimedia Chat. The sign up procedure is not documented though https://meta.wikimedia.org/wiki/Talk:Wikimedia_Chat#Registration

For Scholia, we are tracking the problem at https://github.com/WDscholia/scholia/issues/2285

I think there should be more then one option here and both WM Chat needs update and Federated chat should be an option (each has benefits and shortcomings) serving different needs and focuses.

I think that sticking to one in probably the best to avoid babelification. I would think that Mattermost is ok, - though I haven't tried it. Matrix.org could also be a solution.

In T335349#8836852, @Aklapper wrote:

Wikimedia Chat is an interesting approach, but it seems not to be directly supported by Wikimedia Foundation

Why does stuff need to be "supported by Wikimedia Foundation" (and what does that even mean specifically)? That's not realistic at all, ever.

The issue is that Wikimedia Chat seems to be run by a single person in the volunteer time available, entirely pro bono. So there is no "service guarantee". With paid manpower from Wikimedia Foundation the service could perhaps be improved.

That argumentation is problematic; it basically says "WMF should take over all and any tools and maintain them forever". There's neither enough humanpower for that, nor is that a good idea... :)

How do the WMF developers communicate? IRC, Phabricator, Slack, Wikimedia Chat?

@Fnielsen: Personally I'd guess IRC channels, Slack channels, Telegram channels, maybe sometimes Mattermost, maybe in rare cases Discord (some of the previous ones potentially bridged, and/or via Matrix), maybe in rare cases Signal, when it comes to "chat systems". And probably Phabricator tickets, maybe sometimes Asana tickets, Etherpads, Google Docs, emails, meetings, on-wiki talk pages, and probably more stuff I'm not aware of (it's not that I had a complete overview or such).
Also, somehow https://xkcd.com/1810/ and https://xkcd.com/927/ come to my mind... :)

@Aklapper IMHO your aggressively push your point of view as the norm. There is no reason WMF needs to do things the same way always.
There is also no reason why WMF should self-host Phabricator as a given and not self-host communication platform that could (at least) bridge others (like Mattermost can to both IRC as basic standard and Telegram as the most popular) ... Lack of following standards and establishing at least guidance is what caused this situation. Anyway we are not the same, our needs are also different and it is OK to have different tools, but lowest standards and inter-operational bridges need to exist. Currently they are mostly exceptions, not as a rule.
Not everyting needs to start and end with 'hacker' cynicism and/or jokes.

@Zblace: I don't see where I "aggressively" pushed any views "as the norm". I shared my view as I prefer people not to have wrong expectations that some WMF folks would suddenly start to (co-)maintain many tools which might welcome more human resources. I do not know why you bring up "cynicism" as I haven't seen any.