The article takes it into a boring direction, and they didn't mention Samsung who is most active in this field. Vendors bypass appstores with their proprietary apps. Once upon a time I had a Samsung phone, and when I configured its email app, I saw Samsung's own servers, and not my phone, logging in to my email server. Which means they stole my password. That's when I tossed out Samsung devices once and for all.

But anyway, here's the courtesy tl;dr of the article:

Can it be done? Absolutely. Will it be done? Most likely. Have many people suggested that it's already happening to them? For sure, all over the place.

Is it allowed by Google, Facebook and the like? Most definitely not. So is it happening? Probably not, it's just a coincidence that you talk about something specific, and then suddenly find all kinds of ads about it.

Here's a dictionary definition of 'coincidence' followed by an explanation from a professor about how our minds have evolved to correlate stuff all over the place and see patterns in them, even though they're just coincidences.