Little expansions at the end of letters to emphasise the shape of a letter and make it easier to read.
Times,
Garamond (tasty),
ZapfHumnst.. hopefully not
Times New Roman.
Due to resolution problems some advocate the universal use of (sans = not) sans-serif fonts on the web as rasterized serif fonts at low res are (usually) mangled and ugly.
Also a CSS font-family: type.