>>In the late 1990s to 2000s, there were so many personal text web sites, public forums and chats in my language, Japanese. Now it's all gone. There is no place

>>In the late 1990s to 2000s, there were so many personal text web sites, public forums and chats in my language, Japanese. Now it's all gone. There is no place in the modern Internet I can enjoy serious text-based communication in Japanese. Because, everyone use the smartphone now and it's so inefficient to write a serious text with it. If you mean forums in the vein of Ayashii World, they still exist in the form of 2channel/Futaba. Unless you mean something else.