[thirdsun]

It's not just banner blindness. Even as a less tech-savvy person I imagine I'd just assume those notifications to be fake, fictive customer stories that serve to illustrate a feature, similar to how "customers" used to rave about knife sets and fitness devices that changed their life on home shopping TV shows.

[puranjay]

Yet people continue to buy knife sets and fitness devices from home shopping TV shows, proving that it does work.

You have to see it as a part of a broader persuasive effort. By itself, it doesn't work. But when it is paired with reviews, testimonials, ratings, high-quality pictures, etc., it adds to the impression that this is a legitimate product