This research investigates how humans distinguish different people with identical names on the web to improve web people search. We asked subjects to classify 20 pages of web peoplesearch results for each of 20 person names and analyzed their decision processes through questionnaire, protocol analysis, and interview. We found that keywords, vocations, works (for a real person, works are those made by the individual and, for a fictional person, works are those in which the individual appears), facial images, and the names of related people are important for distinguishing individuals. We proposed a model for distinguishing individuals and a knowledge-structure model based on the experiment's results.