It's easy to underestimate the size of the Flash gaming market, I'm tracking > 120m uniques a month and that's just the tip of the iceberg.
When a Flash game is very popular 1000s of other websites copy the swf file and host it themselves exposing their own audience to that game - and CTC is 3 very popular titles.
Unique users in the 100s of millions? I'm doubtful.