Some of the challenges in World of Warcraft require players to group together to complete them. These usually take place in dungeons—also known as "instances"—that a group of characters can enter together. The term "instance" comes from each group or party having a separate copy, or instance, of the dungeon, complete with their own enemies to defeat and their own treasure or rewards. This allows a group to explore areas and complete quests without others interfering. Dungeons are spread over the game world and are designed for characters of varying progression. A typical dungeon will allow up to five characters to enter as part of a group. Some dungeons require more players to group together and form a "raid" of up to forty players to face some of the most difficult challenges. As well as dungeon-based raid challenges, several creatures exist in the normal game environment that are designed for raids to attack.
To create a new character, in keeping with the storyline of previous Warcraft games, players must choose between the opposing factions of the Alliance or the Horde; Pandaren, which were added in Mists of Pandaria, do not commit to a faction until after the starting zone is completed. Characters from the opposing factions can perform rudimentary communication (most often just "emotes"), but only members of the same faction can speak, mail, group and join guilds. The player selects the new character's race, such as orcs or trolls for the Horde, or humans or dwarves for the Alliance. Players must select the class for the character, with choices such as mages, warriors, and priests available. Most classes are limited to particular races.
In South Korea, there is no software package or CD key requirement to activate the account. However, to play the game, players must purchase time credits online. There are two kinds of time credits available: one where the player is billed based on the actual number of minutes that will be available, and one where the player can play the game for a number of days. In the former, time can be purchased in multiples of 5 hours or 30 hours, and in the latter, time can be purchased in multiples of 7 days, 1 month, or 3 months. As software packages are not required, expansion pack contents are available to all players on launch day.
In the United States, Canada, and Europe, Blizzard distributes World of Warcraft via retail software packages. The software package includes 30 days of gameplay for no additional cost. To continue playing after the initial 30 days, additional play time must be purchased using a credit card or prepaid game card. The minimum gameplay duration that a player can purchase is 30 days using a credit card, or 60 using a prepaid game card. A player also has the option of purchasing three or six months of gameplay at once for a 6–15% discount. In Australia, the United States, and many European countries, video game stores commonly stock the trial version of World of Warcraft in DVD form, which includes the game and 20 levels of gameplay, after which the player would have to upgrade to a retail account by supplying a valid credit card, or purchasing a game card as well as a retail copy of the game.
In patch 2.1, Blizzard responded to this by adding additional anti-spam mechanics including whisper throttling and the report spam function. Additionally, trial accounts are prevented from speaking in the public chat channels (although they may speak to players within range or whisper to other players that have first whispered to them), participating in in-game trades, and using the Auction House and the mail feature, among other limitations.
The practice of buying or selling gold in World of Warcraft has generated significant controversy. On February 21, 2008, Blizzard released a statement concerning the consequences of buying gold. Blizzard reported that an "alarmingly high" proportion of all gold bought originates from "hacked" accounts. The article also stated that customers who had paid for character leveling services had found their accounts compromised months later, with all items stripped and sold for virtual gold. The article noted that leveling service companies often used "disruptive hacks ... which can cause realm performance and stability issues". In April 2015, introduced a means to sell in-game gold for real money. A player may spend $20 on a one-month "game time token" that can be sold for in-game gold on the auction house.
A number of facilities are available for characters while in towns and cities. In each major city, characters can access a bank to deposit items, such as treasure or crafted items. Each character has access to personal bank storage with the option to purchase additional storage space using in-game gold. Additionally, guild banks are available for use by members of a guild with restrictions being set by the guild leader. Auction houses are available for players to buy and sell items to others in a similar way to online auction sites such as eBay. Players can use mailboxes, which can be found in almost every town. Mailboxes are used to collect items won at auction, and to send messages, items, and in-game money to other characters.
World of Warcraft runs natively on both Macintosh and Windows platforms. Boxed copies of the game use a hybrid CD to install the game, eliminating the need for separate Mac and Windows retail products. The game allows all users to play together, regardless of their operating system. Although there is no official version for any other platform, support for World of Warcraft is present in Windows API implementations Wine and CrossOver allowing the game to be played under Linux and FreeBSD. In addition, the Windows client allows for direct OpenGL rendering in Wine, making performance on Unix-like platforms comparable to the native performance seen on Windows. While a native Linux client is neither released nor announced by Blizzard, in January 2011 IT journalist Michael Larabel indicated in a Phoronix article that an internal Linux client might exist but is not released due to the non-standardization of the Linux distro ecosystem.