"It is not really about monetization. It’s about engaging your users and giving them ways to advance in game play, measure their progress and add an extra layer of fun into the game."

The author nails it right here but is wrong IMHO about the % of games that can handle virtual currencies gracefully.

Sometimes I just want to enjoy a good game without being herded repeatedly with a cattle-prod into purchases i don't want to make.

Too often, in-app monetization is a hack-job that takes away from the gameplay experience. One reason why the vast majority of "hardcore" games are pre-paid.

Our consumerist obsession with free has hobbled our producers' ability to create quality. I get excited about the new crop of companies helping gamedevs pay the bills without nickel and diming their players to death. I hope they will lead to a golden age for quality social games.