Internet games refer to online video games that are played over the Internet. These include browser games, play-by-email games, MMORPGs, MUDs, and multiplayer games such as Counter-Strike and Halo. Internet games usually allow people to play together, although in the case of some browser games this is sometimes limited to a shared "high score" list. Many Internet games have associated online communities, making Internet games a form of social activity beyond single player games.