The single most blatantly shadiest digital marketing I have seen, is one that appears to change every year, yet always remains the same.
Con artists learn about some new aspect of search engine optimization.
It can be real, fantasy, or even myth.
Yet when they learn about it, they package it into a training course.
They create highly polished, slick videos for it. Marketing videos. Teaching videos. Sales videos.
They create a web site for it. The web site has all the shiny objects, to dazzle you with stories of wealth and riches and never having to work again.
They create workshops around it.
One day, two day, three day workshops.
They sell the main "course" for thousands of dollars.
They sell add-on videos, add-on courses, guarantees of one-on-one coaching, the workshops, all for thousands of dollars each.
And people sign up. Suck it in. Ingest it. Digest it. And go on to fail miserably.
Or go on to create courses of their own, that THEY then package, and sell.
Nobody ever REALLY succeeds with the techniques, not in a sustainable way. The only REAL success is the sales of the courses, videos & workshops. People selling garbage, yet people buy the garbage.
Some see amazing organic growth. But then that collapses.
Others see growth, yet the growth in reality, is due to OTHER things they have done, overriding the secret special methods they paid thousands to learn.
As long as I have been doing digital marketing (January, 1995 was my start), people have been doing this.