You would be surprisingly sad to learn the number who do not even attempt to do this, and the "marketers" that encourage it.

It's absolutely rampant on any social media platform, and most blogs. I'm guessing it's extremely rare anyone is prosecuted for violating the disclosure laws. Some choose to do it to keep their viewers trust, but one big problem as platforms go all-in on algorithms, it's less about having a trusting audience and more about doing what you can to get random videos/posts picked up by the algorithm, regardless of content.

Those FCC regulations are for broadcasters.

No they’re not: https://www.ftc.gov/business-guidance/resources/disclosures-...

Whoops, missed FCC vs FTC. Anyways, there are similar regulations from the FTC.