Theorists have suggested some people find it easier to express their "true selves" online than in person. Among 523 participants in an online study, Shyness was positively associated with online 'Real Me' self location, while Conscientiousness was negatively associated with an online self. Extraversion was indirectly negatively associated with an online self, mediated by Shyness. Neuroticism was positively associated with an online self, partly mediated by Shyness. 107 online and offline friends of participants provided ratings of them. Overall, both primary participants and their observers indicated that offline relationships were closer. However, participants who located their Real Me online reported feeling closer to their online friends than did those locating their real selves offline. To test whether personality is better expressed in online or offline interactions, observers' ratings of participants' personalities were compared. Both online and offline observers' ratings of Extraversion, Agreeableness and Conscientiousness correlated with participants' self-reports. However, only offline observers' ratings of Neuroticism correlated with participants' own. Except for Neuroticism, the similarity of online and offline observers' personality ratings to participants' self-reports did not differ significantly. The study provides no evidence that online self-presentations are more authentic; indeed Neuroticism may be more visibly expressed offline.