Besides being a word in the name of WeChat, so is also widely used in literary works. For example, in the novel Dubliners by the famous British writer James Joyce, there is a short story called So. In this story, so does not represent a specific meaning, but has more metaphorical and nihilistic meanings. The appearance of So makes readers pay more attention to the relationship between themselves and others in the attitude of all beings.
In the modern context, so is more used to express emotions and attitudes. For example, on social media, if a person answers "so sad" when asked a question, then people can feel this person's sadness and frustration. Similarly, when drying food in a circle of friends, if you say "delicious", it means that the food is very delicious. The use of so makes people express their feelings and attitudes more freely, and can also cut into life and daily life.