This paper discusses the specification and development of social Web services using commitments. Social Web services establish and maintain networks of contacts, count on their (privileged) contacts when needed, form with other peers strong and long lasting collaborative groups, and know with whom to partner so that ontology reconciliation is minimized. To guarantee the proper execution of these operations, social Web services need to comply with the regulations of the social networks in which they have signed up. This compliance is verified using commitments. Two types of commitments are identified: social and business. The former connect Web services to social networks. And the latter connect social Web services to composite social Web services. A proof-of-concept system to detect commitment violations is, also, discussed in this paper. © 2012 ACM.