58 CHAPTER 3 User Authentication FIGURE 3.12 Evite offers users a clear opt-in option for sending party tips and planning ideas. For example, in an e-commerce application, if users are asked to register at checkout, return them to the page they are likely to see if they were already reg- istered or logged in, such as the shipping information page. Related design patterns For many web applications, registration may be the first form users encoun- ter. To create a successful user experience, it's important to follow the patterns identified in Chapter 2--CLEAR BENEFITS, SHORT FORMS, REQUIRED FIELD INDICATORS, and ERROR MESSAGES. When presenting the registration form to users, it is important that they be given an option to LOG IN since they may have registered previously. In addition, because CAPTCHA often accompanies registration, follow the best practices identified in the following pattern. CAPTCHA Problem The application needs to make sure that the action (e.g., register, provide feed- back, send comment, and so forth) is initiated by a human rather than an auto- mated agent to prevent creation of fraudulent accounts and fake responses. Solution Ask users to type characters from a distorted image that contains letters and/or numbers before they can register or provide comments or feedback (Figure 3.13 ).