Advertising - a load of wank

Each day, like most office monkeys, I engage in a variety of email conversations with various collegues and friends. One such friend, an Enviromental Policy Analyst for a Power Industry lobby-group (a paradox, I know), today stated that the advertising industry is a "load of wank". Before responding to this slur, I asked him to clarify what exactly he meant by a "load of wank". His response (cut and paste from his email):

"To use the analogy - if you have intercourse with someone, it produces a useful thing (or at least it has the potential to do so). If you wank, it produces something, but it’s of no real use – it’s primarily for self-gratification. Advertising, while resulting in an output, is fairly useless in terms of being productive apart from the point of view of wealth creation. The information needed to make informed purchasing decisions can be provided by the sellers of the goods and services themselves. In fact, as a customer I would argue that you generally seek it out yourself when you wish to make an informed decision because you don’t trust advertising to give you the whole story anyway. All the industry really does is create wealth for itself, by providing a service that nobody really “needs”. It’s customers are not really in a position to be able to establish a correlation between advertising $ spent and $ revenue earned – there’s too many variables. That said, the industry clearly would have to be delivering benefits to its customers or they presumably wouldn’t continue to spend the $ they do on advertising. But what is this wealth worth in terms of useful outcomes for society? It is arguable whether companies that achieve growth through brand reputation – the ultimate achievement of advertising – are really contributing much to society. They generally sell consumer products – crap we don’t really need that allows self-gratification. Hence, 'a load of wank'."