Steam is a digital distribution, digital rights management, multiplayer and communications platform developed by Valve Corporation. It is used to distribute and manage (sometimes exclusively) a wide range of games and related media entirely over the internet, stretching from one-man independent efforts to some of the world's most popular games. Steam is set apart from its peers in terms of functionality primarily by its residency in the system tray, and the desktop tasks that the client software performs, which will be detailed in the article, to make use of that position.
The system itself works similarly to a feed reader: The user selects the game they want on their computer and Steam then automates the process of downloading the content and keeping it up to date. The latest version of the game is immediately downloaded, and if there are multiple versions (e.g. a 64-bit edition) the correct one will be chosen automatically based on the computer's hardware and/or software environment. This process happens every time Steam is started online, not just when a game is installed, ensuring that as many users as possible have the latest software. Steam transfers content over its own protocol, as opposed to a standard protocol such as  or . It downloads only from dedicated "content servers" spread out across the world by Valve and authorized third parties, connecting to several at once to try to ensure a fast and stable connection.
Steam can validate its downloaded content for errors, a process that gives many of the benefits of reinstalling in a fraction of the time.
Steam has a Distributed File System that allows a game to launch before it has been completely downloaded. By creating lists of files and requesting them only when about to be needed, a linear game can be begun with only the executable code and a buffer of the first few areas downloaded. In the worst-case scenario, the game will stall while Steam downloads in the background.
Steam-integrated games download to non-compressed archive files with the extension
.gcf. This helps to make games more portable, to stop users from overwriting important files, and can be used to prevent files from being tampered with (for instance, the creation of "pure" servers that do not allow custom textures or player models that may give unfair advantage).
Valve Anti-Cheat, Valve's proprietary anti-cheat system, has been incorporated into Steam.
Steam's interface treats mods in almost exactly the same way as it does purchased games, including, for some, browsable pages on the official site This is in contrast with most games that offer no built-in launch utility at all. Mods appear in a user's list of installed games with the icons, developer links and other such details that are used by full games. They can also use VAC, Friends, the server browser, and any other Steam feature supported by their parent game. Currently, mods for Valve's GoldSrc games, Valve's Source games and Red Orchestra can be integrated.
Games available on Steam are priced on varying levels, where older games tend to be less expensive, and newer releases tend to be the same as the retail prices. Gamers have been critical of Steam for the high prices it charges for games added through the other publishers.
On September 12 2007, Valve released "The Steam Community" website, a social network that allows Steam users to communicate with each other on a many-to-many scale, from both the desktop and an "overlay" program that can be accessed within 3D-accelerated games.
Each user's "SteamID" account page contains information such as their Friends (i.e. contacts), how long they have played individual games in the past two weeks, their "Steam Rating (a 0-10 scale of how much overall playtime has been logged in the past two weeks), and of which groups they are a member.
Steam's server browser allows users to search, filter, bookmark and join internet and LAN games for the titles that integrate with it. It works from the desktop and from an integrated game's menu system, and polls Friends to show a list of servers to which a user's contacts are connected.
Friends, Steam's instant messaging tool, supports both one-to-one and many-to-many conversations, held publicly or privately, and Peer-to-Peer VOIP. It provides extended information about what games each user is playing, allowing others to join their contacts in Steam-integrated multiplayer games with a single click.
The Friends system is a popular attack vector for phishers. Complaints have also been made about the practice of 'invite spamming'.
As a centralized system, Steam also allows Valve to enforce regional lockout on their games. This became an issue when some North American customers bought Valve's The Orange Box from Russian and Thai retailers. The retailers were issued authorization codes specific to their regions. When Valve noticed that these codes were in wide use on computers located in other countries, the company disabled their use outside their intended region of sale.
Users who already owned either Half-Life 2 or Half-Life 2: Episode One and who purchased The Orange Box are eligible to give "Gifts" of these games. Valve does not allow these gifts to be bought, sold or traded because doing so violates the Steam Subscriber Agreement, and Valve may disable the Steam accounts of users who are believed by Valve to have done that.
"Free Weekends" are multi-player promotions in which a game becomes free to play on Steam for a weekend. When the promotion ends participant users can no longer play the game, but the game's files can remain installed on their PCs which would save time in downloading future updates if they purchase the game.
Steam has also allowed Valve to run the subscription-based Valve Cyber Café Program, which is the only legal way for a cyber café to offer Steam-based games. There are two pricing models: a flat-rate per-client fee each month, or the "Valve Time Tracker" system that offers a pay-as-you-go model.
The client application, Steam version 1.0, was first made available for download in 2002 during the beta period for Counter-Strike 1.6. At that time, it appeared to be a method of streamlining the patch process common in online computer games. Installation and use of the Steam program was mandatory for CS 1.6 beta testers, but Steam remained an optional component. In 2004, the World Opponent Network was shut down and replaced by Steam.
Recently, Valve has been negotiating contracts with several publishers and independent developers to release their products on Steam, typically with a pre-order discount of 10% off their MSRP. Rag Doll Kung Fu and Darwinia are two examples, and Canadian publisher Strategy First announced in December 2005 that it would be partnering with Valve for digital distribution of current and future titles.
Region restrictions are unpopular with Steam users affected by them, and supported by the media a Steam community group called "Rest of World. was set up on April 1st, after Ubisoft announced the sale of their titles on Steam to only North American territories, with the intention of lobbying Steam publishers about releasing games region free.
Some of the difficulties in selling a retailing game worldwide are detailed by a forum post from a member of Valve's staff:
Sometimes publishers are split into mostly independent North America/European/Asian divisions and one division doesn't have the rights to distribute in all areas. In order to distribute in all areas we have to negotiate deals with all the different divisions and they all have different ideas of how pricing should work and how important digital distribution is for their games. We are always trying to help them understand the importance of markets around the world as well as help them understand the importance of fair and equal pricing for all regions, but it's an ongoing struggle.
While Valve does not have region restrictions on their own games, they do use Steam's authentication to prevent boxed versions of their games sold in Russia and Thailand, which are priced significantly lower than elsewhere, from being used outside those territories.
Regional pricing on Steam is also a controversial subject. It is widely used by publishers to artificially ensure that prices on Steam stay comparable to or above the retail price of a game in user's area, which considering regional differences and exchange rate fluctuations can lead to dramatic differences. Thus, as of April 2008, Call of Duty 4: Modern Warfare costs $49.95 USD in the United States but $88.50 USD (not AUD) in Australia.
It is necessary to validate every Steam game online before it can be launched, although an offline mode is available. There are no alternate methods of activation such as via telephone or fax, which causes the system to deny access to those without Internet connections. According to the Steam Subscriber Agreement, Steam's availability is not guaranteed and Valve is under no legal obligation to release an update disabling the authentication system in the event that Steam becomes permanently unavailable.
Temporary system failures may occur preventing users from activating their games. The first temporary system failure affected Europe on November 2004 just after Half-Life 2 was released, and in December 2006 the root authentication servers were unavailable due to storms in Seattle.
Auto-updating can be turned off by the user, on a game by game basis. Doing this will cause multiplayer games to not function due to the users version being out of date compared to both other users who took the update, and game servers. Choosing to update the game is possible without re-activating the auto-update feature.
Gaming sites have criticized Valve for not making Steam natively available on Mac OS X or Linux; Valve describes the system as "strictly a Windows application". Despite this, Steam can run with most of its functionality under Wine. There have been rumours that Steam and the Source Engine are being ported to other operating systems, but no plans have been announced by Valve.
When a buyer purchases a boxed game they must authenticate it with the registration of a CD Key. In the event that the CD Key that they have registered is already in Steam's database the user is required to submit an image of the physical purchased CD Key for verification purposes, as well as a purchase receipt. Valve does not accept receipts from eBay or known game resellers.