The following questions are all weighted equally (2 points each). Please be brief.

1. Say what each of the following acronyms stands for: WYSIWYG; QBIC; MUD; GUI.
    
2. What is the "Principle of Virtuality" and who is responsible for it?
    
3. Briefly define Ackerman's notions of escalation hierarchy and collaborative filtering.
    
4. Explain parallel coordinate plots and give an example.
    
5. What is Shneiderman's "visual-information-seeking mantra"? Why is it important?