User?bility
One Plus One Equals Three — “People (real human beings with feelings and emotions) interact with web sites (and other forms of experience design) to do all sorts of activities. Some are task-driven (online banking, booking a flight, checking weather reports, for example) but many more are offering experiences where the term user seems both anachronistic and inaccurate.”
Personally, I like saying “user” and I think it is a fine term. The term “participant” makes it sound like every person is in some research study. A user is someone who uses things. Nothing more, nothing less. Nevertheless, I think talking about terms (syntax and semantics) is important. Clarity is a Good Thing.