What do you really know about runes? The ones from our world comes from the ancient Vikings, and their “futhark” (equivalence of our ‘Alpha Bet(a)’). They allegedly hold magic powers, and the magicks of the ‘runa’ are still practised today. These practices, called “Seden”, are of course done mostly as a pastime, but some forms of the old runes were used in proper form as late as early 20th century in the ‘Dalarna’ area of Sweden…
In Sanctuary however, runes are definitely magically inscribed symbols that will grant (sufficiently prepared) items magical properties. For sages of these runes, magical RuneWords can be created to remake a mundane item into a Runic Item, with powers competing with magical artefacts.
As for Diablo II, we have actually a list of all runes, how to CREATE other runes, and how to make all the Runewords. We even have lists of all the runewords for all the types of items they are meant for. Sure, this is a lot of information, but it IS the DiabloWiki, and should you find something to add, you will help the entire community by pitching in. Don’t worry, in a wiki, there is no accidental deletion of information; ANY edit you make will in most cases be a good one! And if you make a typo or an error, it’s easy for you or someone else to fix it.
The Runes article is the new Featured Article on DiabloWiki, go check it out!