Dave Balter and his hive of BzzAgents have published a white paper to trigger some thought provoking discussion around ROI models for social media and word-of-mouth.

Called “Valuing Advertising’s Original Medium: The Conversation,” the Bzz team tries to make a case for assigning value to word-of-mouth in a CPM environment, arguing that while advertisers recognize the benefits of consumer-generated media they really don’t know how to calculate a value to the medium. That’s not easy to do.

It’s an intriguing idea, especially when you consider the team’s methodology resulted in a whopping $300 CPM for word of mouth campaigns. BzzAgent does great work and like many in social media circles today, the need for better measurement models and tools remains very high.

If you don’t like the paper you can at least check out why Dave has the coolest CEO photo on the Web.