Communication networks' influences on the information diffusion process and the effects of 2 virtually identical communication programs were studied. These programs were implemented in 2 Dutch neighborhoods with different levels of cohesion. It was expected that information diffusion would be related to the number of network ties, whereas program effects would be related to the strength of network ties. Data were collected from a representative sample of the target group by means of pre- and posttest surveys and 5 small process surveys. The data confirm the main hypothesis and also provide some support for the strength-of-weak-ties hypothesis (Granovetter, 1973). No significant interaction effects of neighborhood and network variables were found. The results provide some insight on how people restrain each other from adoption and how this is related to the strength and number of communication ties. Persuasive communication is predominantly studied as an isolated, one-way phenomenon between a receiver and a source who tries to influence the receiver's attitudes or behavior through some channel by means of a persuasive message. Most researchers have placed a strong accent on cognitive processes inside individuals (cf. Roberts & Maccoby, 1985). The social context in which persuasion attempts take place has received much less attention in research on persuasive communication. Evaluation studies of public communication campaigns are illustrative in this respect. Most of these studies have focused almost exclusively on campaign outcomes of attitudes or of behaviors rather than on the process by which these outcomes were obtained. Remarkably little is known about the manner in which these outcomes might have been affected by informal interpersonal communications among receivers. This is surprising considering that as early as the 1940s and 1950s, researchers had demonstrated that mass media directly influence a small part of their audience at best, but that face-to-face contacts with other people influence most people (e.g., Katz & Lazarsfeld, 1955; Lazarsfeld, Berelson, & Gaudet 1948). How and by what channels this influence takes place has not been thoroughly investigated. The lack of this kind of research is even more surprising in the light of the community-based communication program that was launched during the 1980s as a promising alternative to large-scale mass media campaigns. Although these programs are largely based on the notion that the social