We've written before about how the bad economy could help the the video game business. Now, a new report from comScore indicates that online video game usage is on the rise in part because Americans are seeking cheaper forms of entertainment.

The online game category attracted 87 million visitors in May, up 22 percent over the same period last year. Yahoo Games was the top destination site for online games with 19.4 million U.S. visitors, though Seattle companies such as WildTangent, Big Fish, MSN Games and RealNetworks' RealArcade were represented in the top 20 sites as well.

But while Big Fish and WildTangent saw double-digit growth, RealNetworks' RealArcade business took a big hit as it lost nearly half of its audience.

Real's online game property attracted 3.4 million visitors, down from 6.1 million in May 2008, according to comScore. That was the biggest drop of any of the sites in the top 20.

Meanwhile, Redmond online game distributor WildTangent attracted 13.8 million visitors, a 16 percent increase over the same period last year. Big Fish, which ranked 12th, saw a 27 percent increase in visitors.

I am sure the health of the industry will be a topic of conversation July 21 to 23 as the Casual Connect gaming conference comes to Seattle. We'll be filing reports from the conference so make sure to tune back into TechFlash.

UPDATE: RealNetworks' Bill Hankes responds to the comScore numbers, saying that the report provides an incomplete picture because it only focuses on the company's RealArcade service.

"The year-over-year decline in RealArcade unique users is driven by the phase-out of our legacy client software and a deliberate shift in focus toward our recently upgraded GameHouse service. The report does NOT include traffic or year-over-year growth to GameHouse.com or to Real’s major international consumer properties Zylom.com and Atrativa.com," Hankes says in an email. "Year-over-year traffic to GameHouse.com, for example, increased about 13 percent according to both Comscore and Nielsen NetRatings. Further, if you combine these direct-to-consumer sites with our extensive syndication and third-party game distribution network, which is a major component of our Games business, you’d see (year over year) growth just south of two percent."

John Cook is co-founder of TechFlash. Follow him on Twitter @johnhcook.