The study is part of a research whose goal is identifying what predictors determine either a positive or a dysfunctional use of Internet. The factor at stake is here social support. Specifically our study, carried out through an online questionnaire, hypothesized a moderation of Offline Social Support in the relationship between Online Social Support, Problematic Internet Use, and Life Satisfaction. The study found that while Offline Social Support reduces the chances of developing a Problematic Internet Use, Online Social Support increases them. Furthermore the data supported the moderation of Offline Social Support in the outcomes of Online Social Support: when the first is low, as the latter increases the Problematic Internet Use gets higher; when Offline Social Support is high, an increase in Online Social Support determines a decrease in Problematic Internet Use. By contrast the moderation of Offline Social Support on the relationship between Online Social Support and Life Satisfaction was not confirmed. Our research show that when investigating psychological constructs related to Internet activity these must be considered in their offline and online variations to provide an answer to the debate on psychological outcomes of undertaking social interactions in Internet land. Our results suggest that the usage of the Web may become dysfunctional when it is meant to compensate for lacks of the “offline life”.