Everybody is talking Social Media and effectiveness. This article by CEO Jan Rezab, SocialBakers has some great proposals for good metrics.
“We determine the return from social marketing based on user engagement – the more users engage with your brand´s content, the better. We created an engagement metric based on that called the Engagement Rate which we monitor across Facebook and Twitter in our Analytics”.
The Engagement Rate for the major social media areas is laid out and ready to use for all. Reach/Fans, Interactions/Engagement Rate and Wall posts/Mentions & Response Rate.
Especially Response Rate is very interesting in terms of how well and often you respond to your fans/customers.
Read the article and see the models here..