I was once asked to do some stats on the marketing effectiveness of a company I was at. Not my job but I really hated a couple of the people in the marketing dept so I went at the task anyway. I had long had suspicious that the advertising was mostly smoke and mirrors so I was glad to find out that I was right. There was basically no correlation to sales and marketing spending, campaigns or anything they were doing. Except for a couple of basic common sense ad placements. They were wasting millions a year.
What do you think happened? Surprise happy ending. At the end of the year they shut down the marketing dept and outsourced the basic ad placements for a fixed fee.