Editor engagement/Email notifications

Purpose of this document: Collaboratively drafted specification for improving the friendliness of MediaWiki's email notifications.

Current format (Wikipedia)

From: MediaWiki Mail

Subject: Wikipedia page User talk:<Recipient> has been changed by <Sender>

Dear <Recipient>,

The Wikipedia page "User talk:<Recipient>" has been changed on
9 November 2011 by <Sender>, with the edit summary: /* Something
something something */ new section

See
<big diff url>
for all changes since your last visit. See
http://en.wikipedia.org/wiki/User_talk:<Recipient> for the current
revision.

To contact the editor, visit
http://en.wikipedia.org/wiki/User:<Sender>

Note that additional changes to the page "User talk:<Recipient>" will not
result in any further notifications, until you have logged in and
visited the page.

            Your friendly Wikipedia notification system

Problem statement

First problem is that email notification are not enabled for watchlist on many Wikimedia projects, as most (non-power) users would expect given that they have few pages in the watchlist and this is how most websites behave (bugzilla:28026).
The sender name "MediaWiki Mail" is silly (bugzilla:32770). The recipient doesn't care that MediaWiki is talking to them, and it's evident that we're talking about "mail". Most email notification services simply use the site's name as the sender name, e.g. "Twitter", "Google+", etc.
- Some would like it to include the name of the user triggering the notification. This would however be confusing for watchlist notifications, because there can be subsequent edits by other users, a possibility which is explained in the body and the sender name shouldn't implicitly exclude.
- Also, "mail" isn't currently localised.
We don't have to describe this actions as the modification to a page. The recipient has new messages: that's the main thing we're trying to bring to their attention.
Note that this is possible only if user talk notifications don't use the same system message as watchlist notifications (enotif_body).
We should gently introduce jargon like "user talk page", keeping in mind that recipients of these notifications will often be new users.
See this blog entry as an example of how the current email messages can be perceived,

Proposed new format (Wikipedia, substitute with different site name as appropriate)

From: Wikipedia

Subject: <Recipient>, you have new messages!

Dear <Recipient>,

it looks like you have new messages on your talk page on 
Wikipedia. It has been changed on 9 November 2011 by 
<sender>. The edit summary was:

    /* Something something something */ new section

This is a link to your talk page:

    http://en.wikipedia.org/wiki/User_talk:<Recipient>

Visit this link to see all changes since your last visit:

    <big diff url>

To contact <sender>, visit:

    http://en.wikipedia.org/wiki/User:<Sender>

Note that additional changes to your talk page will
not result in further email updates until you have 
visited it.

Yours,
Wikipedia

Additional considerations

It would be nice to have an HTML-formatted version of the email for HTML clients.