Actually, there are supposed to be five basic font families. As well as the four I listed in my last post, there is a family called “fantasy.” 
What qualifies a font to be included in this family? The answer is: not belonging in any of the first four. In other words, it’s just a sweeper, and no designer would use it unless the aim was to produce random effects on different visitors’ computers. We can ignore it.
The list of eleven more detailed options I gave is my own, designed to make sure that any text that I am responsible for appears with some sort of similarity across platforms. Some would add Century Gothic and Franklin Gothic to the list, since they appear on most PC and Macs. (They are both sans-serif fonts.) And for a more comprehensive list, with visual examples, have a look at this popular list of “browser-safe fonts.”
