Is Culture Jamming Effective? What does that even mean?

I’ve always wondered how effective cultural jamming really is. Does a parodic advertisement truly make the viewers avoid the product the original ad intended to publicize? Although Christine Harold in her “Pranking Rhetoric: ‘Cultural Jamming’ as Media Activism” provides an in depth look into the complexities of culture jamming as a form of activism, the first few paragraphs made me doubt the actual effectiveness of such practices. Harold begins her essay with the telling of an Adbusters campaign that was supposed to “revolutionize capitalism”, the Blackspot campaign against Nike. Harold also chooses to mention that The New York Times Magazine called it one of the “best ideas in 2003”.
Than how come I have never heard of this before?
For such a revolutionary idea, it is amazing that I have never heard seen or felt any repercussions from that campaign. Also, last time I checked Nike was still a worldwide corporation making ludicrous amounts money. This seems to me like an example of how culture jamming techniques work in theory but have yet to produce actual change in cultural practice. Ad parodies such as the iRaq posters presented to us in class lead me to question how we understand such parodies as “effective”. If it is to produce a shift in ideas or train of thought most “fake ads” are effective because it take a considerable amount of ignorance to view one of the aforementioned iRaq posters and believe that Apple is making a statement on the war in Iraq. But how many of the viewers of such advertisements actually did something about it once understanding the message? If agency is the goal, these ads are severely ineffective.
But is agency the goal of such jamming practices? I should hope so. What good can come of a shift in thought if there is no shift in societal practice?
Perhaps I am being pessimistic about the importance of cultural resistance, but apathy seems to be the most common trait in youth today. Most Canadians likely know about the HIV/Aids crisis going on in Africa and the rest of the world, but it is only a select few who actually do something to help the situation. Perhaps they read a “subvertisement” and developed that necessary sense of agency, and perhaps their motivation came from elsewhere. Either way only the future will tell whether culture jamming techniques can produce a significant change in society.