Mailing list guidelines

Discourse is not a mailing list, but there are many valid use cases for mailing lists. Consequently Discourse supports most of the functions of traditional mailing lists in parallel with its principal function as a modern and advanced web based forum.

Mailing list

Mailing list functionality is enabled by default for all new users. If you do not want to receive email this can be turned off the user preferences.

You will receive emails for all posts, just like a normal mailing list. You can reply to posts in topics directly from your mailer.


Discourse supports a taxonomy of categories. Threads are called topics and must belong to some category. Messages in topics are simply called posts. Our normal thread for most discussions is called General.

Email initiated topics

Discourse in its support of a mailing list model also allows the creation of new topics initiated by email. To do this send email to:

The mail subject becomes the topic name. Email initiated posts go the the General category, there is no choice about that, and that default cannot be changed by the end user. This simplifies things, and in fact reflects most normal mailing lists where there does not exist a categorisation schema.

Note that topics can be replied to freely from the web interface or email. You do not have to stick to one or the other.


Sent mail contains a subject line designed for clarity and to enable it to be simple for you to make filters in your email client program. Subject lines look like:

[The Jackrail] [Category] Subject

Reply addresses

When replying to a post the address will have a special from that enables it to be threaded into the topic in Discourse. These look like:

The Jackrail

This address is constructed from fields in the mail RFC 822 header. Please don’t attempt to alter that, or it simply wont work.

Note that you cannot reply personally to the originator of a post. This function has been a controversial topic in mailing lists for decades and there are good reasons not to support it. Discourse does not. Use the Message function in the web interface to send private messages to other users.


In user preferences you can choose to receive mail in digest form, as per standard mailing lists. Digest of posts are sent periodically, but not clock based, rather, determined by several administrative parameters such as traffic volume and other metrics. Consequently digest posts do not follow a simple periodic send out.

Subjects when replying

Please do not change the subject when replying. Pure havoc results - on almost any mailing list or forum. This is one form of thread hijacking, and it’s a perennial problem for admins. If you want to change the general subject or area of discussion in a topic, just make a new topic, on the web interface. This is very important so as to a) keep topics on subject, b) avoid messing up threaded email client views, c) help make topics readable by not confusing issues. It’s so important that a policy of this forum is that users who persistently hijack threads will be warned by moderators, with possible suspension if non compliant.


You can include images in your posts and they will be displayed in both email and on the web interface. Please use attachments for images and not inline. Inline images cause problems with a lot of systems. You can add as many images as you like. There is a 40MB limit in upload attachments.


It’s conventional in Discourse to not add a signature to the bottom of your email, as the user name on the forum is readily visible in the topic, and it just takes up valuable screen space. It’s not rude to leave it out.


Since mail is complex, every user has a different email client, and things can sometimes go wrong, I have created a special category and email address you can send to for testing:

Messages sent to this address will appear in the Test category if correctly received. When having suspected issues, please try this before reaching out to our moderators or admin, and if there are failures, then forward that information.

Read-only categories

Some categories in the forum are for administrative or informative functions and not for general discussion. You can’t reply to them and mail erorrs will result if you do. The categories Forum Meta and Site Usage are two such. [I have not yet figured out a way of indicating this to users on the site!]


The Jackrail is not a commercial organisation, but I try to offer detailed support for people having issues. Sometimes issues are due to a particular email client program, defect or usage. Since there are so many email clients, I cannot possibly support them all. I will do my best, but it needs to be said that there is a characteristic among mail users that they like to stick with their favourite mail program and it is surprising how many people use mailers that are simply out of date and unsupported. I am unable to offer help with old, unsupported, or obsolete email apps.


Please trim replies, as per normal mailing list etiquette.

Unicode is fully supported.