OpenType (OT) is a cross-platform type format that includes expert layout features to provide richer linguistic support and advanced typographic control. Using OT technology you can substitute your characters for different glyphs1 using many different methods; Ligatures, Small Caps, Oldstyle Figures, Fractions, Superscript/Subscript, Ordinals, Alternates, Titling Characters and many more.
This beginners guide will help to illustrate some of the more common features found in OT fonts and when they should be used.
via Beginners Guide to OpenType — MAGNETSTUDIO.
