The topic of interaction is a complex beast.
A quick search of the online gospel that is Wikipedia returns a number of definitions spanning several fields, including Biochemistry, Sociology and Genetics, among other subjects I know next to nothing about.
But what does interaction mean to those of us working on the web?
“Interaction – It’s important!™”
Today, there’s simply no escaping interaction on the web. To overlook interaction considerations when designing and developing a website is a sure-fire shortcut to failing your potential users.