I ran across an article on the TypeKit Practice blog about OpenType features and how to enable and use them on the web.
OpenType features are more than just fancy swashes, they’re the superpowers of fonts! The best typefaces are full of sophisticated reasoning and little surprises — things that are often integral to the design of the typeface itself, or that help it work better for specific typesetting tasks. Being a graphic design student, I can appreciate the nuances of ligatures and old style numbers, and have always struggled to bring these same features from print over to the web.