Companies need to create some relationship with their customers because everyone has different values; by finding the values a person may possess that are beneficial to the brand and specifying the message to those people, it is easier to penetrate that market.
A problem, however, is the need to be careful with what kind of conversation the brand is trying to start. In the case of the McDonald's attempt at a hashtag, I was immediately able to think of the issue that inevitably did arise.