Social network analysis is one of the important tasks for cybersecurity field to identify some potentially important members in the hackers’ forums and communities. To create the social network of the forums and communities, we need to understand the social structure of them. Once the metadata from each forum is collected, the social structure is constructed based on the users’ interactions such as who replies to whose post and when the response is posted. However, most of the hackers’ forums are unstructured, and there is no way to find the interaction between the users. We introduce the Next Paragraph Prediction method that returns true if a response is a direct response of the previous post. This method helps to create the social structure from an unstructured forum. We evaluated our method with 10 different topics’ threads about the cybersecurity related field, and the method shows above accuracy on average with the largest training dataset.