This is a great posting by Mark W Schaefer all about the social media measurement ney-sayers he recently encountered. The post got 38 replies in a day or so...that's some ROI and just shows the importance of the issue. I still can't believe there are big firms who do nothing...monitoring or analysis. Just crazy how they can justify putting their heads in the sand.
This sort of thing is challenging. To make it work requires real thought; you can't just pick a solution off the shelf. Organisations are unique, as are their methods and delivery, and therefore should be their measurement. It also needs educations and PR needs to learn not to be frightened of numbers.