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.

User experience
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

This feature will appear to the editor after an edit is saved successfully and the read-mode of the page is loaded. At that time, a notification will appear on the article, giving the editor confirmation that the edit was saved or another form of feedback related to their edit. This notification will be more prominent than other forms of currently-available notifications, such as the "new messages" banner, but will be temporary and dismissible.

Technical requirements

 * Message will be displayed to user after submission of edit.
 * Message will appear in a notification box.
 * Message will display on the article page in one of three places:
 * aligned top and left with the chrome
 * aligned center horizontally, between the article/talk tabs and the article title
 * aligned center horizontal and vertical on the separator line beneath the article title if user clicked on main edit; aligned center horizontal and vertical on the section separator line if user clicked on section edit link.
 * Message will disappear after 20 seconds.
 * If the message is one that appears on every edit, users have ability to opt-out of further notifications

Experiment methodology and analysis requirements
See Meta