As games release on more platforms and multiplayer becomes a more integral part of gaming, many games have begun designing games to allow for cross platform multiplayer (often shortened as crossplay or cross-play), enabling players on different platforms to play together online. Adopted widely on computer platforms in the early-2000s, cross-play is typically seen as the standard between PC, Mac, and Linux, due to the similarities between the systems' and early efforts such as Steam Play. Cross-play between different consoles, or between consoles and computers, was uncommon in the early-2000s, but became more common starting in the eighth and ninth console generations.
Occasionally, cross-play may be enabled between some, but not all, of a game's platforms. This may be done due to the content difference between a game's computer and console versions (such as with Terraria), to ensure a level playing field in competitive games (such as in Overwatch, where cross-play is split between consoles and computers in the game's competitive mode), or due to publisher disapproval (such as with Fortnite: Battle Royale cross-play being disabled on Mac and iOS due to the Epic Games v. Apple lawsuit.)
Note: This concept refers to cross-play which enables different console families to play together or with computer platforms. For cross-play between console generations within a console family, see Cross Generation Multiplayer.