User Experience Design is a concept that is fundamental to how we experience information and services in an electonic age.
User experience is a term used to describe the overall experience and satisfaction a user has when using a product or system. It most commonly refers to a combination of software and business topics, such as selling over the web, but it applies to any result of interaction design - Wikipedia
I will not attempt to explain all the facets of this concept but further information can be found at:
What I did want to share was a very informative resource I found that focuses on helping product teams who are creating new or iteratively improving applications for thinking work.