By Mark Ward
Technology Correspondent, BBC News website
The online game World of Warcraft is hugely popular with more than five million people now regularly spending time in Azeroth, trying to turn apprentice adventurers into fully-formed heroes.
Blood elves are part of the Warcraft expansion too
World of Warcraft is a Massively Multiplayer Online Role-Playing Game and, as that lengthy title implies, gives gamers the chance to control characters in a large net-based fantasy world.
Characters can be one of several different races, that includes humans, orcs and cow-like creature called Tauren, and can take up a profession as warrior, thief, wizard, priest and so on.
But for some Warcraft players slaying monsters and gathering treasure is not enough. Instead of swords they are using economics as a weapon.
This is because for all its fantasy trappings, one aspect of Warcraft is alarmingly similar to the real world and that is the importance of money.
Game cash in the form of copper, silver and gold coins helps characters buy better weapons and armour so they can stay alive longer and climb the ranks of their chosen profession.
And it is in the making of money that many players are starting to exploit the freedom of the game world.
Powerful characters need cash to buy their mount
Most Warcraft players' efforts to build up a bankroll for their character revolve around the in-game auction houses.
In these virtual sale-rooms players earn cash by selling the loot that drops off monsters when they are killed. Others players auction off the raw materials they find in the game world so others can use them to make magic potions, magical items or other useful items.
But use of the auction house does not begin and end with bidding, buying and selling - many are turning use of it into as much of a game as adventuring in Azeroth.
Evidence for this can be found in the fact that at the recent BlizzCon conference, the biggest cheer about the forthcoming WoW expansion went to the news that it will give every city an auction house.
Some Warcraft players have turned into so-called "farmers" but this does not mean that they have turned their swords into ploughshares.
Instead "farming" is jargon for those that stay in one area of the game world and repeatedly kill particular monsters just to get at the coveted loot, be it arms or armour, that they drop.
In Warcraft many farmers repeatedly go through the game's "instances" - stand alone dungeons - because the monsters in them are guaranteed to drop rare items.
Stocked up with this loot, the farmers travel to an auction house and flog their gear for gold.
Paul Younger, co-editor of the worldofwar.net site, said many of these pro-players live in Asia and the game currency they get hold of is sold for real cash.
At the time of writing, 1000 gold pieces of Warcraft money sold for about £50. Since online games started to appear currency, items and characters for them have been sold via eBay and specialist sites that do nothing but trade in game gear.
More money means better equipment for your characters
Edward Castronova, a professor at Indiana University who studies the economics of game gear sales, believes that annually gamers are spending at least $200m (£115m) to buy currencies, accounts and characters.
Many use specially written programs to control the in-game characters and only intervene to fend off other players or suspicious community managers from Warcraft controller Blizzard.
Others abuse loopholes in game code to make items or rack up huge amounts of virtual cash.
Mr Younger said "gold-farming" was risky as it could get players banned from the game. But he admits that bans will not stop the farmers because the companies behind them make so much cash by re-selling game gold.
"Although Blizzard bans players caught farming by removing their account it would be practically impossible to prosecute the companies carrying out these operations," he said.
Some look to maximise their returns by controlling the price of a particular item. Every time this item turns up on the auction house, the player buys it, then puts it up for auction again at a higher price to the keep the profits rolling in.
Some have taken this to ridiculous lengths. In April 2005 two players on the Elune server bought all the tradable items on sale in the Ironforge auction house. They then promptly put everything back up for sale at a significant mark up.
You even need cash to fly to new places in Warcraft
But one player who has turned playing the auction house into almost an art is Alex Tabony. He uses a Warcraft add-on program called Auctioneer to fine tune his exploitation of the auction house.
He describes his method as "pure bot reverse engineering".
Via Auctioneer, Mr Tabony can find the highest price that items have sold for in earlier auctions.
Many people use this function of the Auctioneer software to track down bargains.
"My method is to artificially manipulate the high selling point of any item," he told the BBC News website. "If you can control the market price of a specific item type for a while you can 'set' the high selling point for other user's Auctioneer data."
Once users get used to seeing items listed for very high prices, Mr Tabony then puts up lots of that item priced way below the high point.
Players snap these up because they look cheap though in fact they may be paying much more than they need to.
It is a method that works with any tradable item, said Mr Tabony, not just coveted and powerful magic items.
By careful use of this price-setting system it is possible to get hundreds, or perhaps, thousands of gold pieces quite quickly.
"The limit is realistically how much time one wants to invest into it," he said.