If it wasn't effective, it wouldn't be a booming, reliable industry for decades. The impact of converting one person to using your brand is huge. For things li

If it wasn't effective, it wouldn't be a booming, reliable industry for decades. The impact of converting one person to using your brand is huge. For things like clothes or shoes, the person becomes walking advertising. For things like food, the person probably has friends -- friends eat together. It's a short term ad that is in reality a long term investment.