Is this really surprising though? Probably not when you consider that kids today aren't totally different in this generation than previous generations. 'Tweens have always liked to socialize, play, and simply "hang out." The difference nowadays is that parents tend to have looser restrictions and the kids can accomplish most of the things they like to do without even leaving a computer chair. The rules and tools have changed.
The article also talks about a 89/10/1 rule that most F2P/RMT games aim for. This rule assumes that 89% of people will play your game for free, 10% will pay the minimum, and 1% will spend lots of money. Apply that rule to the recent announcements that both Free Realms and Runes of Magic have surpassed 1M users. If the rule applies, it means 100,000 people are paying the basic fees (~$5/month) and 10,000 are spending oodles on extras ($15+/month). That's roughly $650,000 per month, which isn't half bad depending on your development costs.