One of the challenges of social media, one of the reasons clients often have difficulty in being able to pay for social media is the lack of standard metrics. Remember: it’s not that organizations don’t want to use social media. They often don’t know how to justify allocating resources towards social media.
BtoBonline ran a sidebar, “Common metrics for social media
And some of the metrics may not apply to every situation, client or campaign.
But it is at least useful to start.