Hello,
Is it possible to make a group where everybody is except people removed from it?
In fact a kind of way to explicitely blacklist people from some categories.
No, discourse permissions are group based and additive, not subtractive.
这是一种变通方法：
- 创建群组
- 选择通过电子邮件域名自动注册
- 找出您网站最常见的电子邮件注册来源，然后将它们全部添加进去，前 10 名将占注册用户的约 95%
- 使用或修改此处 链接 的群组成员进出脚本，以找出那些被遗漏的人，具体方式可根据您的需求调整。
更简单的方法可能是：让信任等级为 0（全新用户）的人在可见的“入门/欢迎来到网站”主题中阅读 10 篇帖子后升级到等级 1，然后设置网站其余部分需要信任等级 1 才能访问。这样，您可以将不喜欢的人降级到等级 0 或直接暂停他们的账号。
关于为网站添加通配符域名注册或类似功能的功能已被多次提及，但这需要一个插件。说实话，我们确实需要这个功能……
Thank you for this detailed reply, I’ll explore your solution.
In fact I imagined giving no rights to all users to a category, except to a group who can read/write. By default everybody is in this group (so all registered users can write in it) but if I remove someone from this group, then he can’t access the category. So my question was more how to put all members in a group (and all new members by default in this group).