北城已空姑娘丢南城仍在少年离
[bĕi chéng yĭ kōng gū niáng diū nán chéng réng zài shăo nián lí]
A rather poetic username translated roughly as: 'North Town Empty but Girl Gone; South Town Still Here Though Boy Left'. It can suggest a bittersweet past filled with memories of love or friendship where people came into each other's life and eventually parted ways.