[ajmurmann]

Your MyFitnessPal example seems more like luck to me than the norm. Ideally Google (or something similar) would naturally suggest MyFitnessPal to you based on your search history and ideally you'd get a comparison with other similar products. If Google knows you are interested in the product, why do they require payment from the vendor to tell you about the solution to your need?

Of course advertisements lead to spread of new products. That just means they work, not that they are necessarily beneficial to users. Every advertiser might believe that their product is beneficial to the user and therefore they are helping the consumer by telling them about the product. In reality that cannot be true for most advertisers.