Metaplot

Metaplot is a common strategy by a role-playing gaming company to reset canon.

In RPGs, the gamer is in charge. Acts of avatar heroism improve or at least alter the environment. The base environment, assuming the DM is lazy, gets bought from a gaming company like Games Workshop. This "fluff" sets out the world and its backstory.

Well, what if Games Workshop needs more dough. They'll put out a new edition, obviously. Which changes the rules, sometimes for the better (TSR 2e -> WotC 3e is a good example) but either way - changed.

With metaplot, the company invents some world-changing event and kicks up the calendar a few years.

The reason /tg/ hates metaplot is that it takes the power from the players. It is a high-handed move by the company and, if not done well, looks like a naked cash grab. One egregious example is Arcana Evolved's restoration of the dragons to overhaul Arcana Unearthed which basically killed it.

Some companies at least try to involve the players. Some examples here: the Greyhawk Wars leading to From the Ashes, Die Vecna Die! leading to Third Edition across at least three settings, Hellbound: The Blood War taking the fiends' teleport away. Such campaigns have a foreordained conclusion, so tend to the railroad. There's also the issue that it sticks players into a specific year in the timeline; you cannot play Rise of the Runelords in the Golarion of Shattered Star. But if designed right, the players can make a difference around the edges.

Retcon is a specie of metaplotting which, by the laws of thermodynamics, cannot involve the players. That has its own page.