Adopting Arial is at the intersection of several classes of bad web font choices: - random, because it ended up being the browser's default sans serif; - s

Adopting Arial is at the intersection of several classes of bad web font choices: - random, because it ended up being the browser's default sans serif; - someone not really interested in typography went through their available fonts, i.e. system fonts and a few random ones, in alphabetical order and "A" offered enough choices for them; - "Arial" is a short simple word, and someone was too lazy to check or remember other font names; - an amateur designer made a pathetic attempt to reproduce totally inappropriate "Swiss" design, badly, or to be even more inappropriately ironic; - "overused" and therefore "fatal to the designer's credibility", in the euphemistic words of the linked article; a designer that doesn't realize that fonts can be overused has less familiarity with typography than the general public and is therefore not a designer.