Procter & Gamble's Bounty is cleaning up when it comes to in-game advertising. The paper towel brand has been featured inside Electronic Arts' Playfish social game "Restaurant City" since mid-June and has added more than half a million fans to Bounty's Facebook page.

Players complete quests to unlock rolls of Bounty towels that clean more quickly than the game's standard paper towels, and then in a more difficult five-day quest, unlock a Bounty janitor who is 30% more effective at cleaning than the standard janitor. More than 2.5 million players have unlocked the paper towels and more than one million have scored the janitor.

"This is a big test for Bounty and P&G as we look to see if we should make further investments into social gaming," said Ihsan Leggett, assistant brand manager for Bounty.

"This is a good example of where we're going in the social media game space," said Dave Madden, senior VP-global media sales at EA. "We've definitely seen an evolution of in-game advertising and the two-way nature of online and social media creating more conversations between the brand and the user."

Indeed, in-game advertising has come a long way since its early days. Static billboards plopped into the scenery or stadiums inside of driving and sports games played on gaming consoles were once the cutting edge, but today's hippest in-game ads are more likely to be, like P&G's Bounty effort, inside a casual social game and encourage gamers to interact with the product to gain an advantage.

"This is what's hot. The past two years have been all about Facebook and Zynga and the millions of people playing social games. And asking how do you monetize that -- is it through microtransaction, advertising, or both?" said Nielsen Games analyst Bradley Raczka.

Another example of this kind of modern in-game advertising was Zynga's "FarmVille" promotion for Cascadian Farms last summer that offered game players the choice to buy the branded organic blueberries that would grow faster and offer bigger cash returns more quickly. More than 300 million plants were reported sold.

"Why try to reach a highly engaged, extremely interactive audience with boring, static initiatives?" said Wes Keltner, co-founder of video game consultancy Gun.

Mr. Keltner said that overall he thinks in-game advertising does not have the same impact it once did, especially in light of the rise of video-gaming communities such as Xbox Live, for instance, with more than 30 million users, where advertisers can hit millions of gamers in pre-roll ads. Those numbers are also growing as more and more people use their connected gaming devices as more general entertainment devices.

"Some of those ads are seeing a 10% to 17% click-through rate. Not bad at all," he said.

And those kinds of high rates, along with sales, are the ultimate goal for marketers. In-game ads have led to more sales in some cases. EA last fall commissioned Nielsen to study a Gatorade in-game ad campaign across six of its sports console games and found that spending on the sports drink increased by 24% in households that had seen the ads.

One thing that hasn't changed for in-games ads is that they have to be relevant. Diehard and casual gamers will be the first to call foul on ads that intrude on game play, or ones that seem shoehorned into a game. "The games have got to be right, it still won't work in 'Call of Duty' or 'Modern Warfare,' but even think back to 'Grand Theft Auto' when gamers said that rather than fake ads on billboards, they'd rather have real advertisers like 7-11 because it makes the game more real. The same is true today," said Matt Klein, CEO of digital media agency Fuor Digital.