Stemming is typically done by a machine to get to a root form of a word while truncation just chops off the ends of words. Truncation is often not linguistically correct and is not language dependent. Who should do it, the computer or the searcher. The transition between when this number comes down and then up defines the word. The words that have the highest number of matches are considered similar.
Most algorithms give similar performance.
Providing reader aids such as a table of contents, index, etc. Document Management - Includes elements outside of authoring such as publishing, distributing, archiving, etc.