You can't block people from posting on an open protocol. The best solution is a mute option at the client level, which most clients have. In other words, you can control what you see, but you can't control what others see or what others say.
You can't block people from posting on an open protocol. The best solution is a mute option at the client level, which most clients have. In other words, you can control what you see, but you can't control what others see or what others say.