Usability and user experience testing is vital to creating a successful website, and only more so if it’s an e-commerce website, a complex app or another website for which there’s a definite ROI. And running your own user tests to find out how users are interacting with your website and where problems might arise is completely possible.
J. Chang, and M. Bourguet. Proceedings of the 22Nd British HCI Group Annual Conference on People and Computers: Culture, Creativity, Interaction - Volume 2, page 123--126. Swinton, UK, UK, British Computer Society, (2008)