I strongly agree with Jessica that targeted advertising is an invasion of privacy.
For example, whenever I browse a commodity on websites such as JD or Taobao, the
corresponding ads will show up on our social media account, offering me a sense of
surveillance.
I feel like the traces I leave on the internet are the prey of big data, which collects personal information. That makes me feel very insecure all the time, sometimes even experiencing paranoia.
Mike raised the point that targeted advertising helps consumers buy products and services relevant to their interests.
However, he did not mention that people are independent thinkers, it is annoying to see ads popping up out of the blue. Overall I would say that targeted advertising brings more cons than pros.