This document discusses the importance and benefits of user testing websites through diy methods. It begins by defining usability as how well users can achieve goals on a product and their satisfaction level. User testing helps remove obstacles between users and their goals, leading to more conversions and money. While we think we know our users, testing reveals how they actually use sites. Common mistakes are obvious, but some bad designs seem good initially. The document recommends testing at all stages of a project with inexpensive methods like remote and in-person testing. Only a few users and tasks are needed, and changes do not need to be big or expensive to make large impacts to metrics like conversions. The key is to test early and often.