A user profile is a visual display of personal data associated with a specific user, or a customized desktop environment. A profile refers therefore to the explicit digital representation of a person’s identity. A user profile can also be considered as the computer representation of a user model. A profile can be used to store the description of the characteristics of person. This information can be exploited by systems taking into account the persons’ characteristics and preferences. Profiling is the process that refers to construction of a profile via the extraction from a set of data. User profiles can be found on operating systems, computer programs, recommender systems, or dynamic websites (such as online social networking sites or bulletin boards).