What do you think about companies, agencies, and other entities using polls and focus groups to determine ways to manipulate others? eg Ads

Polls and focus groups are used extensively in developing advertisements and political campaign marketing. The outcome could be considered manipulative. Is it manipulation? Just smart? Effective influence? Tools of the trade? Fair?

What do you think?

After the posting of some comments below, I've added the following.

Let me add a slight twist. Let's say Company A claims diet pill X will make you lose weight while eating whatever you want in whatever quantity you want. They bring in focus groups to find the best means to "sell" it to the public? They package it just right, they say just the right things, and provide the right images. People flock to it only to discover it doesn't really work. Is it manipulation? Smart marketing?

Further, what if we later discover that Company A knew diet pill X did not lead to weight loss. Manipulation? Effective influence?