I always feel bad for companies trying to show off a higher resolution screen -- if my screen has a lower resolution, by definition it's kind of hard for my screen to accurately portray its quality; at best I can only see what my screen can deliver.
The photos in this article do the best job I've seen; they show close-up images of text at various DPIs, demonstrating the visibility of the pixels at lower DPIs. (It would have helped to have an image of the same text to view directly at normal size rather than zoomed in.)
