[sc]

Historically, Arial rendered better on Windows than Helvetica, so to offer Macs a form of Helvetica over Arial, you'll generally see:

  font-family: "Helvetica Neue", Arial, sans-serif;

[hboon]

Yes, and GHFigs is pointing out that the article said:

  font-family:Arial,Helvetica,sans-serif;

which is self-defeating.