It has passed into conventional wisdom that both Facebook and Zynga have mobile “issues.” Today’s Wall Street Journal rehashes Zynga’s mobile woes. The most interesting bit has Zynga execs acknowledge that they’re considering charging for mobile apps, rather than count on the virtual-goods-buying “whales” they tap on the web. I’m not sure why the user ratios would be different, but it’s a healthy debate. Our GigaOM Pro spring consumer survey showed that 22 percent of online adults with mobile phones regularly play games, and that figure doubles for smartphone owners. That’s pretty consistent with casual web gaming participation since the dawn of the Internet. Of course, not all mobile is “mobile.” My GigaOM colleague Kevin Tofel points at a survey done by Keynote Systems where consumers self-report their behavior on phones versus tablets. I’m a little surprised the differences aren’t more pronounced. More puzzling: I don’t understand why the survey shows only single-digit gaming on either device. Caveat emptor.