[...] enabling stalking (by making it trivial to subscribe to mentions for another person, rather than yourself). the mitigation mentioned was to make it consentful and two-way [...]
Another option could be to make it not trivial but instead more weighty, to make it clear that the action is to publish a message asserting that some other feed is yours (and have the option be in a menu or settings screen rather than appearing conspicuously on every profile page). Then social norms should inform its use: if someone is sameAs-ing feeds that obviously are not theirs, that would be weird.
I think some uses might require reciprocal identity assertions, but some might not.
I don't think that is the case with Patchfox since to add new identities, you need to load the secret file for that identity into Patchfox. You can't simply name a feed id yours.
In the past, I talked here about maybe using a new message — which iirc I called
groupWith — that would be sent by both identities, not unlike the mythical
sameAs, but would only be used for grouping mentions and helping you add your own identities as recps in private msgs. That could still be useful.
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