This game genre is a subgenre of multiplayer games with the exception that they use large open worlds instead of small rooms typically seen in older multiplayer games. Newer io games also typically have large rooms with many players to bump into. However, they lack more in-depth worlds compared to the MMO genre. The most famous MMORPG game is, of course, Blizzard Entertainment's World of Warcraft game. In the recent past, it was nearly impossible to make an MMO browser game due to limiting factors with the technology at the time. Now, multiplayer games with large worlds are easier than ever before. The ancestor to MMO games is the text-based MUD or multi-user dungeon game genre. MMO games offer unparalleled social gameplay not possible in any other game category. It is pretty common to combine the large multiplayer worlds with fantasy and role-playing aspects. However, there are other MMO games that play with other themes like space operas, first-person shooters, and combat simulators among other gameplay concepts. It is an exciting time for browser games and MMOs.