lucy24 - 9:32 pm on May 20, 2013 (gmt 0)
That's like asking what colors should be used and why.
"What colors to use" can be a perfectly legitimate question, especially if your target audience includes people other than your immediate peers. 19-year-old gamers have one set of preferences and expectations. Middle-aged philosophy professors have a different set. If you use the wrong colors, some readers will take one look and leave. Make sure they're not people who might have been interested in your content.
Granted, you don't get a lot of people taking one look and leaving your site because they don't like the fonts. Unless it's something really outrageous.
:: insert obligatory reference to eleven-point pale-grey Courier* body text ::
* I hunted down the site and checked. It isn't Courier; it's some other monospaced font. But it really was appalling.