Not long ago, MySpace announced it was going to use the personal details in members' profile pages and blogs to better target advertising on the social networking site. The information culled was in addition to users' registration data, potentially offering a powerful combination of demographic data and personal preferences, interests, likes and dislikes. But the promise of targeting advertising to brand advocates and potential customers based on social media consumption (and more importantly, production and participation) remains largely unfulfilled.

In theory, this type of targeting should be both highly effective and highly desirable to advertisers; yet, the reality is social media marketing is driven more by publishers' need to de-commodify their inventory and less by advertiser demand. Participation in social media remains unproven as a targeting metric. While the two are not mutually exclusive, behavioral targeting provides a more compelling solution to advertisers for finding consumers in non-contextually related inventory, at least for today.

Why does behavioral targeting trump social media? What are the barriers to a larger marketplace for social media as an advertising platform? Will marketer demand increase?

Author notes: Marissa Gluck is co-founder and managing partner at Radar Research. Read full bio.