Sure, the film is full of black militant stereotypes and much of the jargon of the time. In that sense, the movie has indeed dated. But as a satirical look at America's number one parasitical industry, advertising, it's still on target. But just as important is the counter- message, namely the effect of big bucks on those who would make the industry more socially responsibleno promoting war toys, alcohol, etc. Thus, the movie's also about the allures of capitalism. Note, for example, how Putney's garb suddenly changes to resemble Third-World revolutionary Fidel's, just before he pulls out of the firm. For a moment, it looks like Swope's mini-revolution has succeeded among his staff, and he's moving on, maybe to spread the movement. But then, the former militants succumb to the allure of big bucks and he departs shaking his head, perhaps to hijack a plane to Cuba. Downey's final word, however, is an ironical one as the Arab (I believe) burns down the money tower leaving the metaphorical structure of (advertising, capitalism) a smoking ruin. To me, this looks like change can only succeed as a cleansing act of destruction and not as a process of reforma message consistent with the radical spirit of the time.
Whatever the subtext, there are some genuinely funny moments, especially with the commercials that play as well now as they did then. Those who compare the anarchic style to that of the Marx Bros. make a good point. The throw-away lines fly thick and fast along with the outrageous set-ups. Forty years later, it's still a hard movie to get a consistent handle on. Despite the crudities, however, the film remains a work of daring originality with some genuinely telling moments.