That's just not that true. People rather frequently do things like share articles they only bothered to read half of on Facebook; there's no reason to think they wouldn't want a newsletter or a product. c.f. http://www.slate.com/articles/technology/technology/2013/06/...
> Schwartz’s data shows that readers can’t stay focused. The more I type, the more of you tune out. And it’s not just me. It’s not just Slate. It’s everywhere online. When people land on a story, they very rarely make it all the way down the page. A lot of people don’t even make it halfway. Even more dispiriting is the relationship between scrolling and sharing. Schwartz’s data suggest that lots of people are tweeting out links to articles they haven’t fully read. If you see someone recommending a story online, you shouldn’t assume that he has read the thing he’s sharing.