When your website users land on a page that solicits their personal information, tradition might tell you to include a pre-checked box that opts the user into an email campaign so they can receive updates and special offers related to your business. Today, having this box pre-checked is in violation of GDPR. So, to comply with GDPR, make sure your European users and customers are given the clear option to opt into your email newsletter themselves -- don't make the decision for them.
That isn’t to say that sales-y promotions couldn’t ever create results—as marketing “gurus” have proved. The results just aren’t as good as they could be. Take the biggest gurus’ results—the ones they boast about—and calculate their conversion rates. Often their marketing is comparatively ineffective. They just have massive volume, so the sales numbers are impressive.