This is a bug in 3.2.1
for site URLs, fixed in 4.0.3
. Replace the link external link with http://netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.min.css
(In HTML, it would be <link rel="stylesheet" href="http://netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.min.css">
)