You answer:

I agree with you, contextual advertising really solves a lot of things when scaling and promoting your product or website. But I wouldn't forget about guest posting, for example, we actively use it in our company, especially since this wonderful service https://adsy.com/ helps us a lot, because in my opinion, all topics related to marketing are complex and therefore we should try to involve only really professional people in solving such a problem. Personally, I like it when you use both contextual advertising and guest posting, it greatly increases the metrics of your site or the product you are promoting.