A recent survey by Flurry has reported that sales of virtual goods have overtaken advertising in top categories on the iOS platform. 

The study was conducted using data from a sample of leading iOS social networking and social gaming apps with a combined reach of 2.2 million daily active users.

Flurry says that the majority of revenue generated from advertising occurred during the 2009 holiday period.  But this year revenue has shifted from advertising to virtual goods sales. So that’s people buying in-game or app items such as virtual swords, gold coins and respect points.

The report points the finger at advertising agencies being too slow to react to mobile as a media platform.

Flurry says it anticipates a stronger ad revenue generation through mobile social networking and games in 2011.