K song system, what's the difference between personal messaging and personal messaging?

There are many ways for people to send messages in karaoke, one is to send messages in the comment area, and the other is that personal messages can also send messages. Everyone can see the information in the comments section. Only two people can see the information in the private letter. For example, greeting each other on New Year's Day, or some personal communication information. Because you are a singer friend from all corners of the country, the general information is in the comment area. Sometimes, I also make a few easy-going friends, just talking privately.