Structured Data's MVP for an image suggestions UI is to send echo notifications to users when they're watching an article that has a suggested image.

We're starting with one experience to be part of the editors flow:

This ticket is to figure out how we might go about that. Specifically we want to find out:

• what kinds of messages can we include in a notification
• can we create notifications from outside a wiki - for example can we run our notification-generation script in the analytics cluster, and push the notifications into the individual wikis from there? if we could it might be neater/easier than running scripts on-wiki
• what's involved in creating a group for receivers-of-these-notifications, and having it be opt-in or opt-out
• is there an existing mechanism to add analytics to notifications so that we can see what open rates are like (and, if possible, follow the user through to adding a suggested image and tracking it to see if it gets reverted)
• can we store whether a user has received a specific notification, and if so, ensure that they don't receive the same notification again?

The outcome of this ticket will be answers for the question above, and any follow-on questions, so that we're in a position to write actual technically-possible requirements and translate those into tickets.