Socialization online sites have become important landmarks for people all around the world and of all ages, especially for youth. Users of such services can socialize with people they know or with unknown, people located in the vicinity or at different distances, even on different continents. In other words, social online sites help people to interact with others of their kind, to know people who have the same passions as they have. The access to such sites is free and the members can build profiles (which include data on name, age, hobbies or favorite books and movies) and can share photos, music or videos with the others. A friend is, in the language of the socialization sites, any user who has a link to his/her profile page. Users can send messages or can leave comments on other profiles. In some cases, people who meet on such sites decide to meet also in the real life.