Continuing the example from the opening comment, Apples should also see notifications from Bananas related to fr.wp when they visit meta, if they (a) have not blacklisted Bananas meta, and
(b) have cross-wiki notifications enabled.

In advance of (or alongside) global blacklists a button to "copy notification blacklist from <drop-down list of wikis>" or even just "copy notification blacklist from meta" would be useful.

Some questions from the meeting:

1. Is it possible to have global blacklist instead?
   1. Does Echo give us the flexibility to add a table/column and store this list for global access?
2. The current implementation (as part of Special:Preferences) will be a hurdle when/if we deploy GlobalPreferences (can't override list globally, need a way to "merge" lists everywhere, basically global blacklist). Can we think about moving it into a new Special page instead? Other options?
3. Is there a use case for having a local and a global blacklist both?

Update for watchers: In estimation today, the Community Tech team (including David and Dayllan of Anti-Harassment Tools sub-team) discussed the pros and cons of having a per-wiki blacklist vs. a cross-wiki blacklist.

From Danny and my product perspective, without cross-wiki baked in from the beginning this Mute feature will not be an effective anti-harassment tool. The workarounds are too easy and too well known for those who would attempt to circumvent the system. But this raises some other questions, which Niharika pointed out in her comment above.

I think it is important for the Mute list to be easily reachable from the Echo feature itself — the 'Preferences' link is prominent in the Echo dropdown itself and is a natural path for users to follow. There are other possibilities — including a separate special page which is transcluded into or linked to from Special:Preferences but the fewer hoops the better.

We've created T171624 as an investigation task which will also serve as a feature onboarding for David and Dayllan into the Echo feature.

I've posted a link to this ticket on Meta and ENWP for people to participate in our discussion.

In T167902#3472128, @TBolliger wrote:

I think it is important for the Mute list to be easily reachable from the Echo feature itself — the 'Preferences' link is prominent in the Echo dropdown itself and is a natural path for users to follow. There are other possibilities — including a separate special page which is transcluded into or linked to from Special:Preferences but the fewer hoops the better.

This isn't really related to cross-wiki-ness but instead to easily accessing the mute feature, right? One thing our team considered while we were working on Echo was to add a secondary action to notifications that would allow you to mute them. Our ideas at the time were about muting by topic/page/type, not by user, but the concept translates. See "Muting from the panel" in T115264#2248740 for a mockup that @Pginer-WMF made at the time.

@Catrope Yes! This is certainly another great UI we could implement — or from the other person's userpage.

I'll make a note of considering this in-notification and preferences design on the investigation ticket. I also like this because it could be extended to topic/page/type in the future.

In T167902#3471195, @Niharika wrote:

Some questions from the meeting:

1. Is it possible to have global blacklist instead?

A "truly" global blacklist would be tricky because it would basically require global preferences, but @Jdforrester-WMF suggests a simpler way to do it could be to make the blacklist preference only available on meta. (Or perhaps it could "live" there but be visible on all wikis with the same value, through some hackery.)

1. Does Echo give us the flexibility to add a table/column and store this list for global access?

"This list" being the blacklist? You could add a global table to track it, yes, but at that point you're basically implementing a global preferences backend. Not saying that you shouldn't, necessarily, but if you're going to do that then I think you should implement a generic global prefs backend rather than a one-off for this feature. (As I understand it, the main reason global prefs are hard is UI/product questions, the backend shouldn't be too hard.)

Seeing as this has been rolled out locally already, one wonders if the questionable use pattern mentioned here has been encountered anywhere.

In T167902#3849434, @JEumerus wrote:

Seeing as this has been rolled out locally already, one wonders if the questionable use pattern mentioned here has been encountered anywhere.

We have not received any reports about this type of behavior. It's certainly possible, and if these tools end up doing more harm than good, we will remove them or make changes.

The Mute feature does not affect Special:Watchlist or its emails.