Probably this could be a good strategy:
- Don’t stop users posting stop words, but change them to *****.
- Notify user he’s just received a penalty point for using bad words. One more such a point and his message will be hidden until reviewed by moderator.
As a result:
- We try to educate, which is better than just preventing posting.
- We discover user intention to write rude things earlier, compared to when we just prevent him sending a message, which will lead him to find a better way to spam.