Namorat, that's to prevent stalking, no?
This is why I use the Line App.
There is a block option in the setting, I've never used it to see what it does, isn't that what it's for? Anyway, the chat at the moment is pretty much useless. Private chat was (mystic) ruined and global and guild are not sufficient. Having a bit more history would help a lot and being able to contact any player will have many uses and could help increase the competition and make the game more enjoyable. For example, in my server right now there is one guild in no1 spot and all the others are way behind, there is no competition. However, if I, for example, could contact the guild masters from some smaller guilds and come up with some sort of alliance things could change. But since they don't use global chat I have no means to contact them.