Hi, just an update on this.This is a real example of an email sent to a mirrored mailing list from an email address (a user) registered in Space: https://discuss-space.wmflabs.org/t/re-wikimedia-education-exciting-update-call-for-submission-of-november-education-newsletter/2247

Such mirrored posts count as contributions from the Space user, and any likes etc are reflected in their user stats.

Here you can see what happens when the email address (the user) is not registered in Space: https://discuss-space.wmflabs.org/t/wikimedia-education-invitation-for-critical-reflections-on-education-open-participation-and-democracy-november-27-berlin/2264

In such cases, Discourse creates a "staged account", like a placeholder. If a user registers with such email address, the posts authored by the staged account will be assigned automatically to the new user, together with its related stats.