This study investigated whether differences in user personality—specifically cognitive and affective styles—impact the user's perception of usability for different types of web sites, since perceived usability is an important aspect of persuasiveness of a web site. For this purpose, different measures of cognitive style and affective style were applied and two versions (high cognitive resp. affective appeal) of web sites educating users about a topic were designed. Users were instructed to explore the sites and rate their usability. Support was found that design for better perceived usability was possible based on need for cognition. Implications were discussed and deeper exploration in future research suggested. In addition, in this paper it was explored whether differences in user personalities matter in information assurance by investigating correlations with concerns for information privacy and user password practices. Statistically significant relationships were discovered.