[SapphireSun]

Essentially, advertising is useful when you need to tell people about a new product or service. Beyond that, it's playing a game. Once people know a service exists and have been accurately informed as to its benefits, then for the most part, people will use it if they need it and spread it by word of mouth if its useful for other people (and/or they had a good experience).

Advertising beyond that mostly serves to solidify brand integrity and trust and ways to undercut competitors and is an ever growing conflagration of an arms race. It has little to do with the interests of the public.