Social media is marketing, not advertising, but it’s got to live somewhere, and it’s got to be measured. So it’s only slightly ironic that the Interactive Advertising Bureau (IAB) would introduce definitions of social media metrics, given social media is the marketing channel that’s actual beginning to replace advertising.

In a hefty 12-page document, the IAB’s “Social Media Ad Metrics Definitions” (PDF download) slices social media into three subsets, and outlines relevant metrics for each. The major categories are defined as:

– Social Media Sites
– Blogs
– Widgets & Social Media Applications

Again: despite the title of the paper, these are definitions that do not apply to advertising, but rather to content marketing. The document emphasizes that value in social media is derived from participation and interaction, sharing, propagating and creating…content. Not ads.

Yet many of the IAB’s social media metrics will sound familiar to anyone involved in online advertising or even site owners: unique visitors, page views, cost per unique visitor, visits, downloads…that stuff just plain makes sense. Yet other metrics related to conversations generated by blog posts, for example, and the “influence” of apps such as widgets are food for thought, as well as fuel for debate.

Debate is good, of course, but not as good as applying quantatative goals and benchmarks to the social media initiatives undertaken by a growing number of marketers. All of whom should download the IAB’s new guidelines and seriously consider which should be applied to their own campaigns.