What happens once you work out the ROI of using social media within customer service?

Organisations seem to spend a lot of time trying to work this one out. There seem to be a lot of assumptions made along the way. And at a time when there is so much change in the way business processes are being run. But the fact that organisations spend so much time trying to work out the ROI implies that working it out is important, as well as the fact that it can be worked out. So I'm wondering what happens when you finally work it out?