Now that Growth features are on all Wikipedias, we can consider whether //autocreated// accounts should get them. Right now, if an account is created on wiki A (and gets the Growth features), and then the user goes over to wiki B (which creates them an account there), they don't have the Growth features on wiki B.
==== Implementation
To ensure the enablement of Growth features is the same on all wikis, the easiest solution is to make use of [Extension:GlobalPreferences](https://www.mediawiki.org/wiki/Extension:GlobalPreferences). In other words, instead of enabling Growth features //locally// on (non-automatic) account creation, we will enable it //globally// in GlobalPreferences.
That way, the state of enablement will be equal at all wikis. On the database level, this can be done by adding rows to `centralauth.global_preferences`, using the user's global ID as `gp_user`. I'm not sure which APIs does Extension:GlobalPreferences offer -- we may or may not have to edit the extension.
To maintain soft dependency on all extensions, I think we should keep the local enabling code as a fallback (when GlobalPreferences is not available for some reason).
==== Open questions
[ ] How will this affect our experiments?
[ ] Is it possible to add global preferences entries via an API?
[ ] The place where users can disable our features will move. Instead of Special:Preferences, it will be possible on Special:GlobalPreferences. Can this confuse our users?
[ ] How should we handle legacy users? Should we migrate everyone to global preferences? Or should we only notify that this is an option?
==== Acceptance Criteria
Given I'm logged in,
When I visit another wiki and an autocreated account is made,
Then the autocreated account has the same "Newcomer editor features" Preferences as currently set in the wiki where I originally registered.
And autocreated accounts should NOT receive the Welcome survey.