There’s no fundamental difference between persuasion and manipulation, in my opinion, except for perhaps maliciousness. Under this way of looking at it, companies that offer value propositions to customers and convince them to buy a better product are engaging in persuasion, while companies hiding the weaknesses of a flawed product are engaging in manipulation.

Life is generally not so plain and simple, and so a lot of advertising behavior falls between these two. Companies will exaggerate, as mentioned by Gabe, and upsell the qualities of their products in order to get more buyers. It becomes difficult to tell sometimes, as a result, whether a company is attempting to manipulate its customers. This is an area where personal opinions dominate- how do you think we should decide if a company’s actions classify as customer manipulation?

One method, albeit flawed, that I like is checking for customer satisfaction. If customers are happy with their products, even if their features were exaggerated during advertising, I feel that the manipulation was relatively benign.