Social networks are popular platforms for interaction, communication, and collaboration. Researchers have proposed applications that leverage social network relationships to improve security and performance in areas like email, web browsing, and overlay routing. However, social network connections alone may not accurately reflect real user interactions. This paper investigates user interactions in Facebook to determine if social links are valid indicators of real user interaction. The study shows that interaction graphs, which quantify user interactions, exhibit different properties compared to social graphs, such as lower clustering coefficients and larger network diameters. The paper also validates two social-based applications, RE and SybilGuard, using both social and interaction graphs. The results show that interaction graphs provide a more accurate model for evaluating socially-enhanced applications. The study highlights the importance of using real user interaction data rather than social graphs for social applications. The paper also discusses the growth of Facebook, user interaction patterns, and the impact of interaction graphs on application performance. The findings suggest that interaction graphs are more accurate in representing user relationships and have implications for the design of socially-enhanced applications.Social networks are popular platforms for interaction, communication, and collaboration. Researchers have proposed applications that leverage social network relationships to improve security and performance in areas like email, web browsing, and overlay routing. However, social network connections alone may not accurately reflect real user interactions. This paper investigates user interactions in Facebook to determine if social links are valid indicators of real user interaction. The study shows that interaction graphs, which quantify user interactions, exhibit different properties compared to social graphs, such as lower clustering coefficients and larger network diameters. The paper also validates two social-based applications, RE and SybilGuard, using both social and interaction graphs. The results show that interaction graphs provide a more accurate model for evaluating socially-enhanced applications. The study highlights the importance of using real user interaction data rather than social graphs for social applications. The paper also discusses the growth of Facebook, user interaction patterns, and the impact of interaction graphs on application performance. The findings suggest that interaction graphs are more accurate in representing user relationships and have implications for the design of socially-enhanced applications.