Many of the online retail and digital distribution clients for PC games started life as a tool for publishers to easily provide games to customers around the globe.  The success and popularity of this distribution, and subsequently marketing, medium has led to most of these clients becoming general distribution and host services still under their parent companies but now offering thousands of titles from many different developers.  Battle.net, Blizzard Entertainment’s online gaming service and digital distribution platform and the first online gaming service incorporated into company games, has not diversified and has remained an exclusive outlet for Blizzard’s PC games.
In its original iteration Battle.net provided little beyond listings and chatting.  Since then it has expanded to host online games, provide matchmaking and tournament ranking, and account management for players’ online profiles.  In 2009 Blizzard upgraded Battle.net to support its new generation of titles.  Since the upgrade all Blizzard games now require a Battle.net account.  Any Blizzard games purchased after 2009 automatically prompt the player to create a Battle.net account after installation.  An account can also be created at the Battle.net website.
Creating a Battle.net account consists of making a login username and password.  Once the account has been created and the client downloaded this will be the username and password the player uses for all Blizzard games.  Blizzard games, when accessed directly instead of through the Battle.net client, have their own login screens but all use the player’s Battle.net username and password.
Battle.net’s origins as an online gaming support service make the software particularly suited to online gaming services such as match-making, in-game networking, and the release and implementation of patches and downloadable content.  Players who do not necessarily own the same game can become acquainted and chat with each other as long as they both have a Blizzard account.  Each Blizzard game has its own homepage interface on the Battle.net client where updates and advertisements from Blizzard are listed and downloads can be managed and implemented.
To date six Blizzard titles can be purchased and are managed on Battle.net.  Older Blizzard games have their own version of Battle.net known as Battle.net Classic which continues to host multiplayer matches and provide patch downloads but otherwise does not provide digital distribution.  Any games that were originally purchased as CD/DVD can be integrated into the player’s Battle.net online account and interface and will be supported in the same way as completely digital products.  Like all successful digital distribution platforms Battle.net does not require a subscription or charge fees for usage.
Since Battle.net only supplies and supports Blizzard games it should not be viewed as a competitor to other digital distribution clients like Steam or GamersGate but more as a business exclusive niche.  Blizzard does not sell its games through other digital distributors so Battle.net is the only digital source for all current Blizzard titles.