One of the gut reactions to theories that invest ads with the power to control how people think or exert subconscious influence, ie, theories that advertisements actually work and convince people to do things against their better or natural interests (why else would it be a billion, if not trillion, dollar industry?), is this: Yeah, sure, ads might work on dumb people, on people who aren't sharp and analytical like me, but I'm intelligent, I'm paying attention, I'm not affected by ads. I'm smarter than they are. Of course this is silly reasoning; ads typically play off one's sense of intelligence to be persuasive, often flattering that intelligence with their own silliness, as in all the ads that simply reject the operation of logic altogether. But when you reject an ad with a sense that you are smarter than it, you nevertheless associate that brand being advertised with a feeling of power in yourself. The ad has done what ads usually want to do (when they are not taking the low road and trying to terrorize you, like mouthwash makers, or tire manufacturers or the Repbulican party) -- it has made you feel good about yourself and associated its product with that feeling of self-satisfaction.
In a short Economist story about telecom business in Somalia (it's great! there's no government there!) the chairman of a the leading cell-phone company there reported how the company had to provide low prices: "Pricing is especially important in Somalia, says Mr Ali, because so many customers are illiterate and immune to advertising." A very interesting point -- not only does one's education (using literacy as proxy here) make one more vulnerable to advertising, but one then bears the cost of that advertising in the form of higher prices. But what this suggests is that ads have a way of affirming the usefulness of education to the person who has it -- it flatters that person. As the saying goes, it's pleasant to know things and pleasant to know you know things; certain ads do what they can to remind you of that, and if you find yourself a Pepsi drinking fool as a result, well, so be it.
Update: This post from the Consumerist blog addresses some of the same ideas. This writer believes that ads are really "cool" and sometimes we don't notice it because we are too busy being unduly negative about advertisements ruling every aspect of our public sphere. "The loud braying ubiquity of advertising pretty much invalidates it without any effort on my part. I don't notice advertising anymore, unless it is advertising that somehow makes my life a little more surreal, or stupid, or silly, or magical. Advertising has oversaturated me, and consequently, I've built up sort of an existential immunity that prevents it from parsing at all. Which makes the occasional advertisement like the two examples above so striking, in that the guys behind it get that you can't just slap a placard up or buy some television space to really get people to notice anymore. Advertising needs to, well, actually be cool to even penetrate the anti-advertising bubble most of us walk around in." I think this is wrong in several ways: when advertising becomes part of the air you breathe, it need not be noticed to be effective. At that level of saturation, it begins to shape your very notion of what's possible, and it becomes harder to even conceive of alternatives to the pictures of happiness as consumer satisfaction the ads supply. No bubble can protect you from the advertising onslaught; when one feels impervious that is when one is most vlnerable, that is when ads have been taken for granted the most.
Also, "cool" advertising can actually work against itself, inviting too much intellectual consideration into one's reaction to what is being advertised. If you admire the cleverness of the copywriter too much, you might neglect the product altogether.
But what's most insane about this comment is that it suggests the writer wants ads to become more aggressive and invasive and illogical, that this writer is worried that ads aren't moving him like they should. He's (or she's; I can't tell) like a kid who has outgrown his cartoons, but doesn't want the responsibility of dealing with more sophisticated mediums. The writer comes across as a perfect example of the narcissist ads work so hard to create, the person utterly dependent on the commercial world for pleasure (reconceived as "entertainment"), the passive, aimless hedonist who waits whiningly for some advertiser to come around and stick the thumb back in his mouth.