In Jodel every spam or commercial post is flagged by our users. Each flagged posts is moderated by a number of moderators. A special algorithm decides if the post has to be blocked or allowed to the app. In extreme cases users can be banned for posting commercial stuff or spam.
We are constantly reviewing the algorithm to make it work better. The details on how it works are never disclosed.
You can read more about it here: https://jodel-app.com/blog/one-year-of-moderation/