The WordPress project has a number of email lists focused on different facets of development. Note that none of these lists are appropriate for user support. The best place for user support is the WordPress Support Forums. For some other support options, see Other Community Sites.
You'll also want to visit Make WordPress. It has overviews of the development teams, update blogs, and additional facet specific documentation. There are many community led teams that don't use a mailing list for their communications.
When joining a mailing list, consider these few reminders that shall keep mailing lists happy and productive places for everyone:
These announcement lists are one-way only and are low traffic (a few emails per year).
This list is meant for major announcements regarding the WordPress project, like new releases.
Information about new APIs, API changes and other news for developers is sent out to this list.
These discussion lists are two-way and can be very high traffic at times (easily dozens of emails per day).
The wp-accessibility list is for people discussing the accessibility of the WordPress administrative interface.
The wp-docs list was created to facilitate coordination and collaboration between members of the community who want to contribute to WordPress documentation. No coding skills required, just a lot of patience. The list tends to be low-traffic, but can have bursts of activity.
The wp-testers list is meant for people to discuss the current nightly or alpha/beta version of WordPress. If you want to discuss the latest nightly or a certain bug report in Trac, feel free to drop in. See Using Subversion for information on where to download development versions of WordPress.
The WP Polyglots group is designed to support and encourage translation and localization efforts for WordPress, often supporting the international community and versions of WordPress. If you have translation and localization coding skills, you are invited and welcome to join the group.
The wp-ui list is meant for people to to discuss ways to improve the interface or user experience of WordPress, and to discuss progress on design-related projects.
The wp-xmlrpc list for the XML-RPC topic relating to WordPress.
The wp-hackers list is meant for people interested in extending WordPress either through plugins or improvements to the core code.
Said another way, "the wp-hackers list is a place for advanced development discussion (hacking) and WordPress core discussion. This means it's not well suited for general development discussion and support questions primarily because a certain level of working knowledge of WordPress and PHP is assumed."
The list can be fairly high traffic at times, if you don't want to subscribe check out the summary.
The WordPress Support Forum Volunteers work hard to help users answer questions about WordPress. Discussions pertaining to providing support to users and WordPress Forum issues and activities are found in the WordPress Support Forum Mailing list. Support questions will not be answered.
If you would like to volunteer to help on the WordPress Forum, we recommend you sign up for the wp-forums mailing list.
THIS IS NOT A SUPPORT MAILING LIST.
It is for Support Volunteers Only.
For specific WordPress support questions, please direct your inquiries to WordPress Support Forum.
The wp-edu list is for people interested in using WordPress in education.
Updates to the SVN repository are mirrored on the WP-SVN mailing list. Whenever a change is checked in to the WordPress repository an email is sent to the wp-svn list with a listing of each of the lines that changed. This is very useful if you want to follow WordPress development very closely. This is an announcement-only list, which means if you want to discuss a change please use the hackers list.
The wp-svn list supercedes the old CVS mailing list.
The archives for the CVS mailing list are available for historic purposes at the following location:
The wp-trac list reports additions and changes to Tickets at Trac, the WordPress bug tracking system.
The wp-meta list reports additions and changes to tickets on Meta Trac. Meta Trac covers various aspects of WordPress.org including the main .org website, buddypress.org, wordcamp.org, the make P2 blogs, handbooks, mailing lists, management of the support forums, theme and plugin repositories, and others.
Issues for these components were previously reported via the main core Trac, but were split off to Meta Trac in mid-2013.
For the Community Mailing Lists, visit the webpages listed above under the appropriate mailing list. You can also perform certain actions on these mailing lists by sending special emails to specific email addresses. Please do not send emails to the list itself asking to be unsubscribed, or removed. Use the webpage for the list or the following email commands :
These email commands work only when you send mail from the mail account for which you want to change or update preferences. In the following section <list-name> stands for the name of the list in questions, such as 'hackers' or 'wp-docs'. If in doubt, remember that the <list-name> is the same as the portion that precedes the @wordpress.org in the email address you use to send emails to the mailing list.
You can request help regarding managing preferences and subscription options by sending a mail to <list-name>-firstname.lastname@example.org with "help" in the Subject of the email. For example, to request help with preferences and options for the wp-hackers mailing list, you should send an email to email@example.com with the word "help" (without the quotes, of course), in the Subject field of the email.
You can subscribe to the list by sending an email to <list-name>-firstname.lastname@example.org with "subscribe" in the Subject of the email.
You can unsubscribe from the list by sending an email to <list-name>-email@example.com with "unsubscribe" in the Subject Field.
If you prefer other formats and venues for support other than the WordPress Support Forums, there are several options available, including: