Short answers, pulled from the story.
MMORPG stands for massively multiplayer online role-playing game. It is a video game genre that combines role-playing game mechanics, where a player controls a character in a persistent fictional world, with a massively multiplayer online format, allowing large numbers of players to share and interact within that world simultaneously.
Richard Garriott coined the term MMORPG to describe massive multiplayer online role-playing games and their social communities. Before this coinage, these games were generally called graphical MUDs.
Meridian 59, released in 1996, is widely regarded as the starting point of the modern MMORPG, notable for its scope and for offering first-person 3D graphics. The genre traces its roots further back through Neverwinter Nights in 1991, and ultimately to multi-user experiments like Mazewar in 1974 and MUD1 in 1978.
Global MMORPG revenues exceeded half a billion dollars in 2005 and crossed one billion dollars in western markets in 2006. By 2008, North American and European consumers were spending $1.4 billion on subscription MMORPGs, and World of Warcraft alone recorded $1.04 billion in total revenue in 2014.
In 2005, a design glitch caused the Corrupted Blood status effect to spread uncontrollably beyond its intended high-level battle zone into the wider World of Warcraft game world. The Centers for Disease Control saw it as a potential model for studying disease progression and human responses to large-scale epidemic infection. However, Blizzard Entertainment did not keep statistical records of the event, so no research results were produced.
MMORPGs use several models: pay-to-play requires an ongoing monthly subscription fee; free-to-play removes both purchase cost and subscription; freemium offers most content free while charging for extras via microtransactions; and buy-to-play requires a one-time purchase with no subscription afterward. Guild Wars uses the buy-to-play model, while titles like MapleStory and Flyff popularized the freemium approach, particularly in South Korea.