The same way we define what is and isn't political advertising? Or tobacco advertising, alcohol advertising etc.
> But, is the SEO I do advertising?
No, it's SEO.
> What about when I share my work to my socials, is that advertising? Post a reel
No, this is just sharing your work.
> Likewise with product placement in films, influencer marketing, etc.
Is it really complicated though? We already regulate what can and can't be said in all these forms of advertising.