Post-edit feedback

This feature is a test of whether giving post-edit feedback to Wikipedia editors enhances their experience, and which kind of feedback is best at motivating them to continue editing.

Current
Currently, one of two things happens when a user saves an edit:


 * 1) if the edit is successful, the page reloads in normal "read" mode
 * 2) the edit fails due to an error such as an edit conflict or loss of session data

There is no system feedback which explicitly confirms that the edit was successful and is immediately live, though if they are aware of it, editors may check the revision history.

Proposed
After an edit is saved successfully, a notification will appear on the page along with the read-mode of the page.

Confirmation and gratitude (test one)
In the first phase of this experiment, a sample of logged-in editors will receive a message every time they successfully save an edit. Depending on which experimental bucket they fall into, they will receive either a dry confirmation that their edit was saved, or a thank you message for making an edit. These notifications will disappear after five seconds and will be dismissable, with the intent that can editors simply scan the page after editing and use the presence of the notification as confirmation of their edit. Since this feature is only designed to support new editors unfamiliar with wiki editing, this confirmation message will only be delivered to editors who registered after the start of the experiment.


 * Confirmation message: "Your edit was saved."
 * Gratitude message: "Thank you for your edit!"

Historical feedback (test two)
In the second phase of this experiment, a sample of logged-in editors will receive a notification when they reach their first, tenth, 50th, and 100th edits. The purpose of this notification is to thank editors for reaching milestones in the contribution history, as an alternative to the current experience where they receive no information about how much work they have done without looking it up using a specialized tool. This notification will look quite different than the previous one delivered confirming every edit, with the intent that newly-registered editors will feel they have accomplished something significant on Wikipedia. Since this feature is only designed to support new editors unfamiliar with wiki editing, it will only appear to those with less than 100 edits before the start of the experiment.


 * First edit message text: "Success! You just made your first edit."
 * 10th edit message text: "You just made your 10th edit. Thank you!"
 * 50th edit message text: "Congratulations, you’ve made 50 edits!"
 * 100th edit message text: "Wow, you just completed 100 edits. Thank you!"

Feature requirements

 * Confirmation and gratitude (test one)
 * A message will be displayed to users in the test every time they successfully save an edit and the page is reloaded in read mode.
 * Users will either see the confirmation message or the gratitude message, never both.
 * The message will appear in a notification box that is overlaid on the page.
 * The message will fade away after three seconds.
 * The message will be dismissible by the user.
 * The message will be visible even if the user is returned to a section via an anchor in the link.
 * The message will be delivered in all namespaces.
 * The message will only be delivered to users who registered after the start of the experiment.
 * The message will not appear after page creation.


 * Historical feedback (test two)
 * A message will be displayed to users in the test after they save their first, 10th, 50th, and 100th edits.
 * The message for each milestone will be unique.
 * The messages will appear in a notification box that is overlaid on the page.
 * The messages will fade away after three seconds.
 * The messages will be dismissible by the user.
 * The messages will be visible even if the user is returned to a section via an anchor in the link.
 * The messages will be deliver in all namespaces.
 * The message will not appear after page creation.

Experiment methodology and analysis requirements
See Meta