Social networking services are among the most applied internet services. Studies concerning post-adoption behavior have focused usage motivations, such as usefulness and enjoyment. Nevertheless, the understanding of consumer behavior in the context of these services is still very limited. Especially, there is no model that integrates the highly relevant switching costs to explain the complex interdependencies within the usage phase. Another specific problem of social networking services relates to the acceptance of revenue models. This study contributes to closing this research gap by proposing a model of post-adoption behavior which covers these aspects. The model assumes two important mechanisms: a loyalty-centered dedication-based mechanism, and a constraint-based mechanism, which refers to the switching costs involved. The focus of the model is widened beyond usage intention to other dependent variables which are crucial from a business perspective, such as usage concentration, willingness to pay and acceptance of advertisements. The empirical test of the proposed model was conducted using a sample (N=208) from users of social networking services. The results of structural equation modeling analysis indicate that the model is able to explain substantially the variance of some of the dependent variables, such as usage intention and usage concentration. Concerning the revenue model acceptance, three positions of users to the financing of service providers are deduced: information seller, privacy concerned user and free rider. Based on the results, theoretical and practical implications are derived.