Abstract
In the last few years, there has seen a marked increase in the usage of Online Social Networks (OSN). Coping with the real time changes of a huge amount of personal information requires new methods for retrieving information. Our previous approach for retrieving information from OSN was a centralized system that controlled and retrieved information of each user's profile once. In order to enhance that approach, a Multi Agent System (MAS) was chosen for its ability to deploy agents to monitor profiles continuously. Since MAS is difficult to implement correctly, a formal specification of an OSN System was constructed to help us investigate the feasibility of using MAS technology in retrieving historical information from OSN sites.