# Moderating open organizations An **open organization** is one where [anyone can join without an invitation](/help/allow-anyone-to-join-without-an-invitation). Moderation is a big part of making an open community work. ## Prevention Zulip has many features designed to simplify moderation: * [Disallow disposable email addresses](/help/allow-anyone-to-join-without-an-invitation) or [require users to log in via GitHub or GitLab](/help/configure-authentication-methods). * Restrict who can [create streams](/help/configure-who-can-create-streams), [create bots](/help/restrict-bot-creation), [send private messages](/help/restrict-private-messages), or [add custom emoji](/help/only-allow-admins-to-add-emoji). * Link to a code of conduct in your [organization description](/help/create-your-organization-profile) (displayed on the registration page). * Create a [default stream](/help/set-default-streams-for-new-users) for announcements where [only admins can post](/help/stream-sending-policy). * Add a [waiting period](/help/restrict-permissions-of-new-members) before new users can take disruptive actions. * [Restrict email visibility](/help/restrict-visibility-of-email-addresses) to reduce the likelihood of off-platform spam. * [Restrict wildcard mentions](/help/restrict-wildcard-mentions) so only moderators can mention everyone in your organization. ## Response * [Ban (deactivate) users](/help/deactivate-or-reactivate-a-user) acting in bad faith. You can reactivate them later if they repent. * Use the `streams:public sender:user@example.com` [search operators](/help/search-for-messages) to find all messages sent by a user. * Delete messages, [delete streams](/help/delete-a-stream), and [unsubscribe users from streams](/help/add-or-remove-users-from-a-stream). * [Rename topics](/help/rename-a-topic). * [Change users' names](/help/change-a-users-name) (e.g. to "Spammer") * [Deactivate bots](/help/deactivate-or-reactivate-a-bot) or [delete custom emoji](/help/add-custom-emoji#delete-custom-emoji). * Instruct users to [collapse](/help/collapse-a-message) messages that they don't want to see. ## In the works * **Delete spammer**. This will wipe the user from your Zulip, by deleting all their messages and reactions, banning them, etc. * **Mute user**. This will allow an individual user to hide the messages of another individual user. * **New users join as guests**. This will allow users joining via open registration to have extremely limited permissions by default, but still enough permissions to ask the core team a question or to get a feel for your community. * **Public archive**. This will give a read-only view of selected streams, removing the need in some organizations for having open registration.