The subject of this research was the playing of online games, so-called MMORPG (Massively Multiplayer Online Role-Playing Game). MMORPG are usually virtual fantasy worlds in which many of the players spend a large portion of their time and a tendency for addiction appears to be quite large for this type of games. Players from our sample spend an average of 27 hours weekly in these games, 13.5% of players however note 50 or more hours weekly in the game, corresponding to about 7 hours of gameplay per day. Our research sample consists of 548 participants (352 from Europe, 181 from North America and 14 from other parts of the world). Players were addressed in forums designated for games "World of Warcraft" and "Everquest" and were asked to fill in a questionnaire found on the web page. The age of players varied between 12 and 55 years, here we are concerned mainly with adolescents (12 - 19 years of age) and young adults (20 - 27 years of age), but we also show a general age comparison of adolescents, young players and adults. 85% of players in our sample are men. In this article we described the answers of MMORPG players related to belonging to a virtual community of players and comparison of groups in the real and virtual world. 66% of players aged 12 - 19 years agree that they experience a feeling of belonging somewhere in the game, 55% of players experience a feeling of their own importance in the game. 36% of players in this age even state that they feel better in this virtual group than in real-world groups. We show that the experience of belonging in a community of MMORPG players is most notable for adolescents, adolescent players also most often prefer a virtual gaming group to real-world groups. The most important factor of preference of virtual gaming communities is the player's absence of a partner (romantic relationship). We have also uncovered a relationship between the preference of virtual groups to real-world ones and the tendency for addiction to the game. A weak relationship can also be found between the tendency for addiction to the game and feelings of belonging to a virtual group. Adolescents are thus proving to be the most threatened by MMORPG addiction, since they most often have no romantic relationship and also have a higher tendency of preferring virtual worlds to the real one.