The article "The Hero's Journey: Are You Experienced?" uses the Dreyfus model of skill acquisition to explain how people learn: Initially, when they are novices, they cannot handle a lot of contradictions. They want to be told what to do and everything must be simple and consistent. Combine this with the observation that abstractions must be built by amassing concrete examples, and one can derive a few rules for teaching (some of them borrowed from "Hero's Journey"):

My guess is that most people will soon find out that constantly being interrupted by one's cell phone makes it hard to relax or concentrate. On the other hand, it is convenient if someone is easy to reach.

Generics allow parameters to determine the type of the return value. This can be used to avoid a cast when returning objects from an internal map, by using the class of the object as a key.

Description:

The UMBC Semantic Web Reference Card is a handy "cheat sheet" for semantic web developers and programmers. It can be printed double sided on one sheet of paper and tri-folded. The card lists common RDF/RDFS/OWL classes and properties, popular namespaces and terms, XML datatypes, reserved terms, grammars and examples for encodings, etc.