[tzs]

It's not a question of whether or not they can exist. It's a question of whether or not they can be effective enough that the advertisers will pay enough for them to provide enough revenue to keep the site afloat.

Someone reading a print article is probably a much stronger signal that they are interested in things related to the article or the topic of the publication than is someone reading an article on a website.

If some random site runs an article about, say, a meteor shower you probably can't infer that the reader has more than a passing interest in astronomy. Even of a site that is focused on astronomy runs such an article they are still likely to get a lot of casual readers, such as people who heard on the news about an upcoming meteor shower and Googled to find more information.

If on the other hand Sky & Telescope runs an article about a meteor shower in their printed magazine it is probably a safe bet that most people reading that have a fairly serious interest in astronomy.

If I were trying to sell astronomical equipment I'd probably be willing to pay a lot more to run an ad in Sky & Telescope than I'd pay to run the same ad on a "free but with ads" astronomy website and I'd pay even less to run it on some non-astronomy site that happens to be running an astronomy article.

I think this largely invalidates most of the "it worked for print so it will work on the web" arguments I've seen except maybe for websites with well enforced paywalls.