In case you haven’t noticed, virtual goods is rapidly becoming the business model of choice for online games. A proof point for that is the latest report from Kongregate, an aggregator of independently developed online games.

Kongregate is announcing today that its virtual goods micro-transaction revenue is growing by 30 percent each month. It would be nice if it said what its revenue was, but the private San Francisco company doesn’t release that data. At least it tells us that virtual goods is working for Kongregate.

The growth rate is impressive for the company’s Konduit application platform, a virtual goods platform launched last December. With the business model, players can play online games for free. But if they want certain valuable virtual items, such as better weapons or decorations, they have to dish out the cash for them.

The success of virtual goods on Kongregate’s platform is good news, as it shows the company has been able to pivot from the recession-battered business model of advertising to something more lucrative. That’s also good for the makers of the 25,000 games on Kongregate’s site.

Kongregate also says it is exclusively launching Remnants of Redstone, a two-dimensional online game played in a browser. This high-end game, developed by Flipline Studios, was able to generate an effective CPM (cost per mil, a measure of ad revenue per 1,000 views) of $86 on virtual item and subscription revenue while it was in a closed private beta. Now it is being released to Kongregate’s 8.5 million monthly unique users.