Comment 11 for bug 810229

General Launchpad email background
----------------------------------

Launchpad follows three simple rules when sending email to a particular
person or team:

 - If the recipient is a person, send it to their preferred address.
 - If the recipient is a team with a contact address, send it to that
   address.
 - If the recipient is a team without a contact address, follow these
   rules again for each direct member.

So a message destined for a team will be sent to every indirect member
of that team, except where one of the teams on the way down the
hierarchy has a contact address.

We discourage teams from opting their members into email. Forcing
people to receive email they don't want just makes them filter it, not
read it. To this end, Launchpad has progressively made email settings
more flexible to let people control which email they receive, to move
toward opt in rather than opt out, and to eliminate the need for team
subscriptions.

Merge proposals in particular
-----------------------------

Merge proposals follow the recipient rules as above, but are the
primary source of email that hasn't yet been fixed to respect the
guidelines around opt-in defaults: each reviewer or requested reviewer
gets emailed on changes to the merge proposal, even if the reviewer is
a team and even if they're not subscribed to either branch, and there's
no way to directly stop that. We'll be giving merge proposals a big
makeover soon, which will fix this problem once and for all, but until
then there is a workaround to stop the spam.

One of the teams just needs to have a contact address set. The team
admins will find an edit link next to the Email field on their team's
Launchpad page, where a Launchpad mailing list can be selected or an
address can be specified manually. Choose the address, follow the
instructions in the email, and the merge proposal notifications will
be redirected from team members to that single mailbox.

You can use any address that you have access to, as long as another
Launchpad person or team doesn't already list that address. It's common
for people to use "plus addressing" to overcome this limitation: many
email services (including Gmail) let you suffix your username with
+anystringyouchoose, so <email address hidden> would end up
in my <email address hidden> inbox.

Using Launchpad itself as an example (https://launchpad.net/launchpad),
our projects' branches have their default reviewer set to
https://launchpad.net/~launchpad-reviewers, a team with a mailing list
configured as its contact address. Our main developer team,
https://launchpad.net/~launchpad, is a member of the review team, so we
all have review privileges and relevant MPs show up on our review
lists. Individuals who want to get email about all our merge proposals
can subscribe to the mailing list, or directly subscribe to just the
branches they're interested in.