蓦然回首曾经爱过一只狗
[mò rán huí shŏu céng jīng ài guò yī zhĭ gŏu]
This net-name '蓦然回首曾经爱过一只狗' can be translated into English as 'Turn around suddenly, once I loved a dog'. This implies the user had deep affection for a pet dog in the past. It may also imply simplicity and innocence of the love, without human's complicated emotions and interests.