NEW YORK (CNN/Money) – "EverQuest II" players are used to buying things in the game.

Need a sword? A couple of gold pieces will fetch you a sturdy one. Hungry? That can be remedied for a silver piece or two. Of course, both the merchandise and the currency are worthless outside of the game.

Changes are on the way to the world of Norrath, though. Starting mid-next week, players will be able to order a real world pizza (with real world pepperoni, even) by simply typing "/pizza" in the game.

It's an interesting experiment on Sony's behalf. Can the publisher introduce advertising to its game world in a way that doesn't seem obtrusive – but still generates a response among some of its 325,000 active players?

Advertisements have slowly been trickling into video games for a couple of years now. That trickle is about to become a torrent, though. And despite all the research, no one's certain how players will react.

Sony is hardly alone in looking for ways to bring in advertising revenue. UbiSoft will include dynamic ads in the next versions of its popular "Splinter Cell" and "Rainbow Six" games. Atari (Research), Vivendi Universal Games (Research) and Take Two (Research) plan to follow suit, as well.

Even Activision (Research), the industry's second largest publisher, is getting interested in the field. Last year, the company announced it was working with Nielsen Entertainment Media to develop a technology that would track both how many in-game ads a player encounters and how much attention he or she pays to them.

For Sony, this is the first step in what will likely be a broader transaction system. When players type "/pizza", a new browser window opens, connecting to PizzaHut.com and allowing the player to place a delivery order. There's no need to log out of the game and leave your fellow players in the lurch as they rush into battle.

"We don't want to do anything that will take people out of the game experience," said Chris Kramer, director of corporate communications for Sony Online Entertainment. "We don't want to create armor that has the Nike swoosh or you have to drink Coke for health. Our subscribers would freak out."

Should the experiment succeed, expect to see similar sales programs go into effect – this time with the billing tied directly to the credit card number players give Sony to cover the game's monthly charges.

"Our goal is to grow our business so that ultimately we're offering a number of services online," said Kramer. "Slash-pizza is the first step. We see a much larger additional revenue stream coming into the company."

Interactive advertising, like Sony's, is a rather unique model. Traditionally, most publishers have blended static ads into a game's artwork. Players, though, quickly ignore those ads after seeing them again and again.

New York-based Massive Inc. sees a middle ground between the two philosophies, however. The company, which claims a dozen publishers as clients, has created a dynamic ad system for video games that it said will be used in more than 40 titles by the end of the year.

By dynamic, we're talking ads that change regularly. An example: Your character may wander by a Dunkin' Donuts store in the game world as you play one morning. In the window, a sign would try to entice you with a box of munchkins. If you happened to be playing the game in the afternoon, though, the munchkins pitch would be replaced with one for latte. And should you happen by that same in-game location a few months later, you might find the Dunkin' Donuts replaced with a Verizon store.

Dynamic ads will also allow film studios and music companies to pitch upcoming movies and CDs in a timely manner – and remove those ads when they're no longer relevant. "Splinter Cell: Chaos Theory" players will be the first to experience this, as posters for the new Motley Crue CD will appear in some in-game bars.

With so many 18-34 year old men eschewing television for games, it's understandable why advertising firms want to reach into the gaming world. But gamers have shown little to no interest when it comes to any form of advertising. And there hasn't been much willingness on their part to change their opinion.

Still, Mitch Davis, Massive's CEO, said he suspects gamers will come to welcome the ads.

"Over 90 percent of gamers think advertising is a net positive for gaming because it adds realism," he said. "Why would they want to see an ad for 'The Goop' and not 'The Gap'? But this is a smart demographic. The advertising needs to be smart. It needs to be creative. And it needs to be relevant. If you overdo the advertisements, you push the sensibilities of the audience."

There's real money in the ads, if nothing else. Sony (Research) declined to talk about the particulars of its deal with Pizza Hut. Davis, though, said Massive's network of publishers add anywhere from $1 to $2 of net profit for every individual game sold. In the next 18 months, he sees that going to up to $4 per copy.

That may not sound like a lot, but for a successful game, it can add up fast. And it can help titles that don't live up to their sales expectations find their way into the black. As an added bonus, it doesn't cost the publisher anything.

It's all for naught, though, if it results in a player backlash. After all, slaying monsters in the world of Norrath may be hungry work, but there are a lot of other worlds to explore.

Morris is Director of Content Development at CNN/Money. Click here to send him an email.