打酱油滴 or 打酱油的 literally means 'buy some soy sauce'.
background story:
several years ago, some photos of a movie star in HongKong were sent out to the Internet by someone, all of them were about himself having sex with other female movie stars. Then one day, the journalist of Guangzhou TV station was trying to interview a passer in the road about this incident, but the passer answered : 'what is the fucking business to do with me? I'm just out to buy some soy sauce~'. (关我鸟事,我是出来打酱油的)
Young people thought this case was quite funny so it becomes more and more popular on the Internet. They use it to mean: It has nothing to do with me, I am just passing by...
Example:
In a forum, under certain topic, people are discussing something, while u add your comment like :大家好,我来打酱油了. That means, hey I am here, and you can ignore me now....