User testing

Basic usability test: Give the user a task, then observe the first thing a user does. Observe the steps taken to complete the task. How easy and straightforward was it for the user? How many errors did the user make? What are the user's expectations? How satisfied is the user at the end -- did it meet user's needs? Usability is important; if it's not intuitive and logical, if there are too many steps and too many deficiencies, the user will likely give up and leave.

Usability Surveys

Surveys are not the best form of measurement when it comes to usability -- they do not measure the true nature of human interaction. But surveys do complement user observations and generally measure frequency, satisfaction and anticipation of future needs. "Surveys are notoriously ineffective for generatin new ideas and approaches" - The Role of Online Surveys in the Usability Assessment Process