“The lesson here is twofold. First, good typography has a clear impact on the mood of the reader. People who are reading a well typeset page are more engaged in the experience and find that time flies by faster. Second, research has shown that positive mood improves creative problem solving, and since typography can be used to influence mood, it is possible that good typography also has direct effect on our productivity, at least in the sphere of certain creative tasks. Good typographic design then is not just a way to communicate the character of your text and strengthen reader engagement, it could boost their cognitive performance, too.”

(Dmitry Fadeyev a.k.a. @dfadeyev ~ UsabilityPost)