User testing involves putting users in front of a website or app and giving them realistic tasks to try to complete. For example, if the client was a clothing e-tailer, one task might be to find a green sweater in their size and put it in the shopping cart. User testing is often done with existing sites to identity "pain points" in the customer experience. For our user testing we usually combine a screen capture with an audio recording of the user's voice, so you clients can see and hear what is frustrating users (as well as what they enjoy!).
However, user testing can also be done earlier in the design process with incomplete designs, like this paper prototype for a smartphone app:
Here are some results from doing user testing for a client's original website. The first table shows how users did on each of six tasks we gave them. As you can see, Task 4 was very difficult for users. This helped us identify places where the website could be improved.
Task success provides an objective measure of whether users can use a site, but it doesn't necessarily tell us how they feel about the site. So, we usually also give users a questionnaire after they complete the tasks where they rate their experience. For the particular questionnaire used here, the typical score is about 68. Since we found an average of 55.3 for this site, users seem to be having a fairly negative experience - definitely some issues to be addressed!