The number of visitors to online computer game websites grew 27 percent in the United States in 2008, reaching 86 million by the end of December, according to comScore figures released Wednesday.
The total amount of time people spent playing games online leapt 42 percent, with 4.9 percent of Internet activities devoted to play.
"It appears that online, ad-supported gaming is one of the activities that has benefited during this economic downturn," said comScore director of gaming solutions Edward Hunter.
"Not only have consumers turned to outlets such as gaming to take their minds off the economy, but as they curtail their discretionary gaming-related purchases they are turning to free alternatives."
Yahoo! Games was the most popular website in the category with visits climbing 20 percent to 19.5 million year-over-year. Videogame giant Electronic Arts ranked second with visits rising 21 percent to 15.4 million.
Disney Games was in third place with visits growing 13 percent to 13.4 million.
"Casual games are providing a really good alternative source of entertainment that is fun and free for people in a tough economic environment," said Michelle Weaver, chief operating officer of EA's POGO game website.
"We are seeing really strong growth. This was a pretty significant jump for the business."
Approximately 37 percent of the time spent on US online play was spent at POGO, which offers more than 100 puzzle, word, board and other games in a social-networking community setting.
The display advertising market at game websites is a bright spot in a dark economy, with a 29 percent surge in the number of times ads are viewed, according to comScore.
"The growth in display ads in the online gaming category not only underscores the assertion that gamers are increasingly accepting of ad-supported games, but also that the advertising community is recognizing the value of this highly engaged audience," said Hunter.
Free computer game play that is all the rage in South Korea has been taking hold in a US market dominated by videogames sold on packaged disks or by online subscriptions.
Seoul-based "free-to-play" computer game titan Nexon last year blasted into the US videogame arena with a "Combat Arms" online first-person shooter title. More than a million people registered to play in the first five months.
The game makes its money from players that buy animated helmets, outfits, emblems or other virtual items to customize in-game characters, and Nexon plans to begin exploring incorporating advertising.
"Free-to-play is starting to catch on fast," said Nexon America spokesman Min Kim. "As more people get into it, word of mouth is spreading. We are carving a space out for ourselves."
California-based Electronic Arts has been investing in free play and is putting finishing touches on a "Battlefield Heroes" war game supported by in-game transactions instead of up-front purchase prices.
Personal computers have become a natural gaming forum as people spend massive amounts of time online at social websites such as Facebook, MySpace and YouTube.
Analysts say that startups and established game makers, including Japanese goliath Sony, are increasingly venturing into the free computer game market.
The free play model is tempting in a US market where packaged video games typically sell for 60 dollars each but has to compete with gamers devoted to consoles.