How useful are Social Media metrics?

In Social Media Marketing, the metrics you choose determine where you go. If you choose 'facebook friends' as a measure of success, you choose one strategy. If you choose 'positive conversations' you choose another strategy.

There are so many metrics that it is difficult to choose which one makes any difference at all. It sounds a lot like marketing-buzz to me. My default starting position is this:

All metrics are useless. Until a metric is proven useful, I assume that it is useless. If I have 5000 facebook friends, does it translate into measurable results? Does it mean that I have a tribe of 1000 friends, fans and followers who will go out of their way to support each other's art?

Arguments about the usefulness of metrics aside, here's a great SlideShare presentation from Cisco on Social Media Measurement. It shows how to organize and present social media metrics.