Online Networking Sites (ONSs) are online communities where individual users maintain a network of connections and actively communicate with them (Ellison, Steinfield, & Lampe, 2007). The rapid growth of online social and professional networking websites calls for an examination of the communication processes that exist and operate through these channels, and the motives behind their use. In order to fill a gaping hole in research concerning ONSs, the present study attempted to examine the effect of antecedent variables on Social Networking Sites (SNSs) and Professional Networking Sites (PNSs) separately. Based on the view that individual users would utilize online networking in characteristic ways, a structural model was proposed which hypothesized that, personality traits, communicative and social influences, attitudes, and motives would affect level of activity on ONSs. Using Uses and Gratifications theory (Katz, Blumler, & Gurevitch, 1974) as the theoretical framework, the proposed model was tested in the current study. The model hypothesized that gender and personality traits would impact communicative and social variables. These were hypothesized to influence attitudes towards ONSs, which in turn, was hypothesized to affect motives to use ONSs. Motives of use, was hypothesized to directly affect level of activity and also mediate the relationship of attitudes on activity. Participants (N = 691) completed measures of personality, shyness, communication apprehension, self-esteem, need for affiliation, attitudes, motives of ONS use, along with measures of ONS behavioral outcomes. Results offered support for the hypothesized model of SNS motivations and activity but not for PNS activity. The lack of results concerning PNSs was explained due to the unsuitability of the current college sample. With respect to SNSs, the results illustrated that these websites were primarily used to maintain relational connections with others. In addition, the findings provided support for the contention that although SNSs offer beneficial social tools for all individuals; this effect was highest for individuals already proficient in offline social and communicative behaviors. Overall, the study illustrated that networking websites acted as inclusive channels for social interaction and as online companions to users' offline social structures.