Using a private off-site email is inappropriate in 99.99% of cases. In a year of moderating, I've never had to do that. It's an option that should only be considered if all else fails (see below). In the event that you do have to send a private email, be sure to bcc email@example.com on it.
One way to contact a user privately is to use the private messaging system. It's available from the user profile by going to
mod->actions->contact this user privately. There is an option to suspend the user along with the message, but it's an optional step that can be avoided. (The corollary is, too, that you can't suspend someone without notifying them.)
The user will be notified of the message on the site and receive a copy in their email if they provided one on the account.
This way should be used when you're notifying the user of an infraction and you can choose from several common message templates.
Sending a mod message (whether suspension is included or not) puts a permanent mark / annotation on the user's account as well as notifies the other moderators on the site and several Stack Exchange employees. Do not use it to respond to the user's flags or for other non-serious issues.
Another option is to create a private chat room. You must not do this just to chat with users or your friends. This option is strictly for moderation issues that do not warrant a private message (i.e. a user asked you a question in a flag and you can't respond to it in public).
Normally, a chat ping (
@username) will only reach a user (via the global inbox) if the user has been in the chat room recently. As a moderator, you may "super-ping" a user, which will generate an inbox notification even if the user has never been in chat. The syntax to do this is
@@<user's id on the site>@<site host name>. For example, to ping Rebecca Chernoff, use
Because the super-ping will only work if the user has access to the room, you should make sure you make the room private and give the user write access to it before you super-ping them.
The most reliable way to do this and ensure that the user has a chat account is as follows:
- Create the room.
- Super-ping the user with a generic message to create the chat account.
- Give the user write access to the room.
- Make the room private.
- Consider whether you really do need to contact the user privately. If you're just responding to a common question in a flag that doesn't reveal any sensitive information (e.g. "is this question on-topic?"), you can respond with a general comment on the question instead. You can also use your site's main chat room.
Direct communication with users aside from sending warnings is fairly rare and whenever possible should be done on meta, in chat, or in comments on relevant posts instead. Look out for opportunities to explain something to everyone rather than just one person whenever possible.