"closing percentage and cost-per-acquisition are rated as the most effective metrics in helping B2B organizations evaluate marketing ROI" - What are you measuring?
Interesting article. This is a great delineation of the maturity of the corporate usage of social media. Implementing ROI in most corporations goes through similar phases, although they need to be much more directed. Social media metrics and ROI will also soon be de rigeur for many of the more sophisticated companies.
It pays to know your audience and to map the engagement path. If your target audience is older, a 'Like' may be a lower value engagement metric than you thought.