Steam

""Oh, yeah, I love Steam! I just hate the pipes...""

- Francis

Steam is the most popular Digital Distribution platform for PC games. Created by Valve Software in 2004 to distribute and integrate their own games cheaply, it has grown from its shaky and buggy beginnings into the service that PC gamers can use for their online middleware needs. (Provided you have a decently fast internet connection and a way of buying online.) It also features a messaging system, an online multiplayer platform, Achievements, and an in-game Web browser, making it something like the PC equivalent of X Box Live, except free, and marketed at an older demographic. And like Live, it has since gone cross-platform, supporting MacOS X in addition to Windows.

All of Valve's PC games since Half-Life 2 have required Steam and the retail versions come with it. The service is free to download as well, and allows gamers to integrate their games into the service, as well as download games that support the service natively.

Having the full support of pretty much every major publisher that makes PC titles except Blizzard, Maxis (except for Spore and Sim City) and recently Electronic Arts, the service makes it easier to just download and play PC games, due to having over one thousand titles available for download, many of which are classic games in their own right-and now it boasts more than 30 million unique users. Not bad for a company that made its first game 12 years ago.

Of course, we have a Steam Group, here. Feel free to join.

The program has its own Hatedom, partly thanks to the service's self-imposed DRM, but also due to surprisingly high prices, which Steam circumvents by offering weekly discounts on specific products. Further, as Digital Distribution has become more popular, some of the ways Steam does things have proven unfriendly to competition. Ironically, the reaction to Electronic Arts' digital service Origin was highly negative, with a ton of people wishing they just stuck to Steam, though this is largely in part due to majority opinion that Origin is not only a vastly inferior service for a variety of reasons (it can be argued that Steam's success is because it provides a variety of useful services nobody else provides), but also due to Orgin's highly controversial terms of service.

In 2010, the interface underwent a major overhaul, designed to coincide with the release of Steam for the Mac. Opinions are mixed.

Not related to water vapor. That will never happen.

Games and series for download from Steam include:

 * Aaaaa a Aaaa AA Aaa AAA Aa AAAAAA Reckless Disregard For Gravity
 * Alan Wake
 * Alice Madness Returns
 * Alliance of Valiant Arms
 * Alien Hallway
 * Alien Swarm
 * Americas Army
 * Amnesia the Dark Descent
 * And Yet It Moves
 * ARMA series
 * Assassin's Creed series
 * Assassin's Creed I
 * Assassin's Creed II
 * Assassin's Creed Brotherhood
 * Assassin's Creed Revelations
 * Audiosurf
 * Avadon
 * A Valley Without Wind
 * Back to The Future
 * Bastion
 * Battlefield series
 * Battlefield Bad Company
 * Beat Hazard
 * Bejeweled
 * Beyond Good and Evil
 * The Binding of Isaac
 * Bionic Commando Rearmed
 * Bioshock series
 * Bio Shock 1
 * Bio Shock 2
 * Bio Shock Infinite
 * Blade Kitten
 * Bloodline Champions
 * Borderlands
 * Borderlands 2
 * Braid
 * Brawl Busters
 * Breath of Death VII
 * Brink
 * Call of Cthulhu Dark Corners of the Earth
 * Call of Duty series
 * Modern Warfare series
 * Call of Duty Black Ops
 * Call of Duty Black Ops 2
 * Cave Story+
 * Champions Online: Free For All
 * Chantelise
 * Chime
 * City of Heroes
 * Civilization
 * Command and Conquer franchise:
 * Command and Conquer Tiberium Wars
 * Command & Conquer 3: Kane's Wrath
 * Command and Conquer Tiberian Twilight
 * Command and Conquer Red Alert 3
 * Red Alert 3 -- Uprising
 * Commander Keen
 * Company of Heroes
 * Costume Quest
 * Counter-Strike
 * Crea Vures
 * Crime Craft Bleedout
 * Critical Mass 2011
 * Crusader Kings II
 * Crysis
 * Cthulhu Saves the World
 * Culpa Innata
 * Dark Forces Saga
 * Dark Messiah
 * Dark Souls - Prepare To Die Edition (Coming Soon!)
 * Darwinia
 * Dawn of War
 * DC Universe Online
 * Dead Island
 * Dead Rising 2
 * Dead Rising 2: Off The Record
 * Deadly 30
 * DEFCON
 * Deus Ex
 * Deus Ex Invisible War
 * Deus Ex Human Revolution
 * Devil May Cry 3 and 4
 * The Dig
 * Doom
 * Dota 2
 * Dragon Age
 * Drawn The Painted Tower
 * Duke Nukem Forever
 * Dungeon Defenders
 * Dungeons of Dredmor
 * Dustforce
 * Dwarfs
 * Earth Defense Force Insect Armageddon
 * Earthworm Jim
 * Ecco the Dolphin
 * Ecco Jr.
 * The Elder Scrolls series
 * The Elder Scrolls III Morrowind
 * The Elder Scrolls IV Oblivion
 * The Elder Scrolls V Skyrim
 * Empire At War
 * End War
 * Europa Universalis III
 * Ever Quest II
 * Eversion
 * EYE Divine Cybermancy
 * Fable - The Lost Chapters
 * Fable III
 * Fallout series
 * Fallout 1
 * Fallout 2
 * Fallout 3
 * Fallout New Vegas
 * Fate of the World
 * F.E.A.R. franchise
 * Final Fantasy XI
 * Flat Out
 * FlatOut 2
 *  FlatOut: Ultimate Carnage 
 *  FlatOut 3: Chaos & Destruction 
 * The Force Unleashed
 * Fortune Summoners
 * Forsaken World
 * Front Mission: Evolved
 * Frozen Synapse
 * Garrys Mod
 * Gemini Rue
 * Geometry Wars: Retro Evolved
 * Ghost Recon series
 * Gish
 * Global Agenda
 * Global Agenda: Free Agent
 * Gotham City Impostors
 * Grand Theft Auto series
 * Grand Theft Auto
 * Grand Theft Auto II
 * Grand Theft Auto III
 * Grand Theft Auto Vice City
 * Grand Theft Auto San Andreas
 * Grand Theft Auto IV
 * Gratuitous Space Battles
 * Guild Wars
 * Gundemonium Series
 * Guns of Icarus
 * Half-Life series
 * Half-Life 1
 * Half-Life 2
 * Hard Reset
 * HAWX
 * H.A.W.X. 2
 * Hearts of Iron III
 * Heavy Weapon Deluxe
 * Hegemony Gold
 * Heroes of Might and Magic V
 * Hydrophobia: Prophecy
 * Il-2 Sturmovik series
 * Il-2 Sturmovik: 1946
 * Il-2 Sturmovik: Cliffs of Dover
 * Indiana Jones and The Fate of Atlantis
 * Indiana Jones and The Last Crusade
 * Iron Grip: Marauders 
 * Jade Empire
 * Jamestown Legend of the Lost Colony
 * Jane's Advanced Strike Fighters
 * Jolly Rover
 * Jurassic Park the Game
 * Just Cause
 * Killing Floor
 * Kingdoms of Amalur Reckoning
 * Kings Bounty
 * Knights of the Old Republic
 * LA Noire
 * The Last Remnant
 * Left 4 Dead
 * Left 4 Dead 2
 * Lego Adaptation Game
 * Limbo
 * Lone Survivor
 * Loom
 * The Lord of the Rings Online
 * Lugaru
 * Lumines
 * Machinarium
 * Mafia the City of Lost Heaven
 * Mafia II
 * Magical Diary
 * Magicka
 * Magic the Gathering: Duels of the Planeswalkers
 * Majesty
 * Majesty 2
 * Defenders of Ardania
 * Warlock: Master of the Arcane
 * Mass Effect 1
 * Mass Effect 2
 * Max Payne
 * Men of War series
 * Metro 2033
 * The Misadventures of PB Winterbottom
 * Monday Night Combat
 * Monkey Island series
 * The Secret of Monkey Island
 * Monkey Island 2 Le Chucks Revenge
 * Tales of Monkey Island
 * Moonbase Alpha
 * Mount and Blade
 * Myst
 * Neverwinter Nights 2
 * Noitu Love 2
 * Nuclear Dawn
 * Oddworld series
 * Oddworld Strangers Wrath
 * Orcs Must Die
 * Patrician series
 * PAYDAY the Heist
 * Peggle
 * Penny Arcade Adventures
 * Plain Sight
 * Planet Busters
 * Plants vs. Zombies
 * Poker Night At the Inventory
 * Post Apocalyptic Mayhem
 * Portal
 * Portal 2
 * Prison Tycoon series
 * Prototype
 * Prototype 2
 * Psychonauts
 * Puzzle Pirates
 * Puzzle Quest
 * Quake series
 * Rage
 * Railroad Tycoon series
 * Rainbow Six Vegas series
 * Rayman Origins
 * Realm of the Mad God
 * Recettear an Item Shops Tale
 * Renegade Ops
 * Resident Evil 5
 * Revenge of the Titans
 * Rift
 * Risen
 * Rise of Immortals
 * Ristar
 * Rochard
 * Rollercoaster Tycoon 3
 * Runaway A Twist Of Fate
 * Rusty Hearts
 * Sam and Max Freelance Police
 * Scratches
 * Second Sight
 * Sonic & Sega All-Stars Racing
 * Sequence
 * Serious Sam
 * Serious Sam the Random Encounter
 * Shadowgrounds
 * Shatter
 * Shattered Horizon
 * Sengoku
 * Sim City 4
 * The Sims 3
 * Sky Drift
 * Sniper Elite
 * Sniper Elite V2
 * Sonic the Hedgehog series
 * Sonic the Hedgehog
 * Sonic the Hedgehog 2
 * Sonic CD
 * Sonic 3 and Knuckles
 * Sonic 3D Blast
 * Sonic Spinball
 * Sonic Adventure DX
 * Sonic the Hedgehog 4 Ep. I
 * ''Sonic The Hedgehog 4 Ep. II
 * Sonic Generations
 * Space Chem
 * Spiral Knights
 * Splinter Cell series
 * Spore
 * Star Ruler
 * Starscape
 * Star Trek DAC
 * Star Trek Online
 * Star Wars Battlefront II
 * Still Life
 * Street Fighter IV
 * Strong Bads Cool Game for Attractive People
 * Super Meat Boy
 * Supreme Commander 2
 * Swords and Soldiers
 * Syberia
 * Tachyon the Fringe
 * Team Fortress 2
 * Terraria
 * Thief series
 * Toki Tori
 * Tomb Raider series
 * Torchlight
 * Total War series
 * Trine
 * UFO Afterblank series
 * Unreal series
 * Uplink
 * Vampire: The Masquerade Bloodlines
 * Velvet Assassin
 * Vigil Blood Bitterness
 * Virtua Fighter 2
 * VVVVVV
 * The Walking Dead
 * War Inc Battlezone
 * Warhammer 40000 Space Marine
 * Warhammer Online
 * Wasteland Angel
 * Winter Voices
 * The Witcher: Enhanced Edition
 * The Witcher 2 Assassins of Kings
 * Wolfenstein 3D
 * Wolfenstein 2009
 * World of Goo
 * Worms
 * X-Universe series
 * X-COM series
 * Ys: The Oath In Felghana
 * Ys Origin
 * Zombie Panic