Why did my friend write 发发发 on her note?
发：Short for 发财，make a fortune，become rich。


Chinese people like to use reiterative locution to emphasize the strong meaning or wish. Other cases like: 好好好、 旺旺旺、棒棒棒、赞赞赞。
Sometimes you will also see 888 instead of 发发发，because 888(bababa) has similar pronunciation with 发发发(fafafa) and much easier to write/type.