Well look at the case study on BT yesterday. The case is there but its based on need, not ROI. In my office, I need my staff and encourage them to use Facebook. networking is an important part of the job. Secondly, employees should be compensated and judged based on results, not the clock. Finally, younger generation employees demand social media... deny them it and they will work elsewhere. There's your case. Notwithstanding that, Sabre has proven there is ROI as well.