Is there a way to allow posting anonymously without users signing up in Discourse?
Not while signed out, only users that have an account, you can enable " Allow Users to switch to anonymous mode" site setting in your forum, for users to be able to switch to a completely anonymous account.
If you use email-in, you can setup an email address for a category that will enable “anonymous users” to participate. This requires “staged users”, then in a category :
You need to setup the engage@example.org email address to forward to your installation’s discourse email (the one you POP.)
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That looks like a good idea! I followed your link to staged users and do not understand the connection. Could it be that you linked the wrong URL?
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Yes, you’re right. I corrected the link.
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I have enabled this setting, however, I’m not seeing how you can switch to an anonymous account? How do you do this?
Click or tap your user avatar at the upper right, then the spy / anonymous glyph.
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I think they’re talking about staged users here though…
Staged users haven’t logged in so that doesn’t make sense to me? You must log in to be able to switch to anonymous.
Agreed. I think there is some confusion stemming from this:
Yes! Thanks for that. Didn’t notice that inconspicuous little icon before. 
Do you understand that a staged user won’t be able to do that though? They are only interacting with the site via email.
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Yeah… Not a problem. The only users I’m concerned about are registered users on my site.
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私の知る限り、これはコア機能ではなく、プラグインでも利用できず、コアでの実装も予定されていません。
参考までに、匿名投稿に関する機能リクエストは 3 件複数回寄せられていますが、実装されているのは 1 件のみです。
登録済みユーザーが（ログインした状態で）匿名で投稿できる機能
未登録ユーザーが匿名で投稿できる機能
匿名投稿のみを許可するカテゴリ（つまり、登録済みユーザーであっても匿名投稿のみが可能）
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この2つの機能の実装もぜひ実現してほしいです。
- 未登録ユーザーが匿名で投稿できるようにする
- カテゴリを、匿名投稿のみを許可するものにする（つまり、登録ユーザーであっても匿名投稿のみ可能にする）
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