Grass (kusa)
Overview
Grass (kusa) is Japanese internet slang that means "laughing" or "that's funny." It came about through a series of changes: "(warai)" (the word for laughing), then "w," then "www," which looks like grass growing, and finally "kusa" (grass). It is used in forms like kusa haeru ("grass is growing"), kusa, and daisougen ("a huge prairie") to show how hard you are laughing.
It is the equivalent of "lol (laughing out loud)" in English, but grass gives a more casual, lighter impression. People don't use it in formal settings, but they use it in conversations between friends and on social media.
Using grass in a question box
In question box answers, one way to use grass is to add a friendly feel or a touch of humor. One grass in an otherwise stiff answer can soften the impression of the whole answer.
However, using it too much can backfire. If every answer has grass attached, it can give the impression that you write without thinking. Also, replying to a serious question with grass looks like you're making fun of the sender.
Laughter in text is hard
Expressing laughter in text is harder than face to face. In person, a smile or laughter tells people "I'm joking," but in text you have to get that across with words alone. Grass, "w," "warai," "😂": without symbols like these, there is a risk that a joke gets taken seriously.
In question box answers, the laugh symbol you choose also shapes the tone. Grass is casual, "(warai)" in parentheses is somewhat polite, "warai" on its own is in between, and the impression an emoji gives changes depending on the platform. Choosing a way of expressing laughter that fits your character and the mood of your question box is also one way to put care into text exchanges.