Not one to miss out on extolling the features of Discourse… 
For anyone not aware, there are a few delete options available to Discourse admins:
- Anonymise User - This is where the details in the user profile are wiped, but all content remains. These posts will then be attributed to eg anon31415926 (more info: Anonymizing Users in Discourse)
- Delete Posts - These are essentially ‘soft-deleted’, and are still available for admins and moderators (and can be ‘undeleted’ if required)
- Permanently Delete - This is the ‘hard-delete’ option where they are struck from the database. This is now possible on a topic/post basis through the UI (more info: Introducing permanently delete post functionality). To delete posts on a larger scale you would need to use the rails console, which may not be available to all admins depending on their hosting (ie. they would need to contact someone with server access)
These are the responsibility of each foum’s admins, so different communities may have different approaches to how and when they deploy them.
(And for the 20-character minimum, it is configurable for each Discourse forum, but we like to stick as close to the defaults as is practicable on Meta so people can get a flavour of ‘Discourse in action’. It also means that if we get a lot of examples where one isn’t working we can change the default. 
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