Ads are still legal, that hasn’t changed. You can still target customer based on the sites the visit or the sesrches they make.

Sales people, well agencies, are just super pissed that they now have to do actual work. For years they’ve been able to make money by clicking around in AdWords and Facebook ads, now the real sales people has to get back to work.

By providing useful products or services?

As a company you need to follow the law. As a company, to attract new customer you sell something useful. Those two aren't mutually exclusive. For example, you can sell a service to a customer even if you respect their privacy.

A couple people here have said "make something useful." Fascinating. So make something useful but then how do you actually get it in front of people without resorting to very expensive and inefficient brand advertising?