忘却江南梦谁忆长安尘

This internet name conveys a sense of longing and loss. 'Jiangnan' refers to a scenic region in Southern China that's often associated with cultural refinement and historical romance, while 'Chang'an' is the ancient name for the capital of China during multiple dynasties, symbolizing politics and fame. Thus this phrase could express that although someone may try to forget a beautiful past or place like Jiangnan, someone else might remember scenes of glory like Chang'an.