My two cents. Article directories will of course have duplicate content but the same can not be said for web directories. However, the 'detail page' (if there is a detail page) can be considered duplicate content.
posting same content on different directories is OK
posting different content on different directories is OK
posting same content/same url on the same directory is Spamming
posting same content/same url on different category in the same directory is Spamming
posting different content using sub page url on different category in the same directory is Deep linking (some directories accepts only index url only) this means no deep linking.
posting same content on different directories is OK
posting different content on different directories is OK
posting same content/same url on the same directory is Spamming
posting same content/same url on different category in the same directory is Spamming
posting different content using sub page url on different category in the same directory is Deep linking (some directories accepts only index url only) this means no deep linking.