Well, this is an unusual post. It's not about current events regarding internet and technology, but rather it's a look back at the field of usability and how we got to call this user experience or HCI or UI design.
Way back when... maybe in the 60's, the field was called ergonomics.Ergonomics then was the study of comfortable and human adapted furniture, architecture, and others... the goal was to make comfortable chairs at just the right height, for instance. So this was applied to computers, so that monitors were not too bright, and keyboards felt just right.
The word User Interface, and it's importance to the design became important in the early 80's. Probably one of the more important developments in the field was the Xerox Star, which contained some of the more important inventions in UI's, such as a Desktop, icons, WYSIWYG, property sheets, universal commands like Copy and Undo, etc. The interesting thing was that this was the first computer to have its UI designed before any code was written. I was lucky enough to work in a project at Apple with Dave Smith, who was one of the main designers of the Star, and one of the authors of the article above.
So by then, talking about User Interfaces became common. And the importance given to it became higher. In the early 90's, two terms appeared that were close, but somewhat similar: User Experience, and User-centered design. User experience was a term coined by Don Norman while at Apple to cover more aspects of the interaction than simply what was on the screen. Given Norman's background in psychology, it made sense to look inside people's heads and talk about experience. This term became really popular with web people in the late 90's, and most people who say they focus on user experience tend have a web background.
A little earlier than this, in 1986, the term User Centered Design started being used. This one is funny. A book called User Centered System Design (UCSD) was edited by Norman and Draper with articles from a number of trailblazers in the field. (including my advisor at Berkeley, Andy diSessa). What is funny about this, is that Norman at the time was the chair of the cognitive science department at University of California at San Diego (UCSD). So the acronym was kind of a joke.
Then in the 80's, academics in the field started meeting in an annual conference called CHI (Computer Human Interaction). But some people thought that humans should come first, and decided to call their field HCI, for Human Computer Interaction. So now we have a CHI conference, but academics who go to it do HCI. Great.
Lately, many products have won battles and dominate their categories based on their ease of use and prettiness. iPod is one: easy to use and cool. Nokia many people say it's easy to use. People don't have time these days, and any product which is easy to use and cool will win over one that is complex and boring. So it's not just about the experience, it's about making things usable. Hence the term Usability. The focus here is on easy to use.
So when I meet someone these days, I say I do HCI, or usability, or user experience. It's all sort of the same thing, it all depends on where you learned your chops and what community you feel you belong to. In the end, it's all pretty much the same thing.