The five keeper ideas I gleaned from this course:

1. Software, games and websites all need to have carefully thought out interfaces to be effective.
2. "Rightness" of design is often defined in the eye of the user, therefore what works well for an adolescent may not work for an office worker.  It is also often a personal preference.
3. We must begin with the end in mind when we start to design, considering the purpose of the site and the user profile.
4. Interface design is an evolving process, with rules that modify based on the discoveries of others and trends that rapidly shift throughout popular sites.
5. It is much easier to see what DOESN'T work than to create and define something that does.