Measuring success in social learning environments

Jane Hart's site lists the pros and cons of social learning in the section of her website that introduces social learning. In part four, "Introduction to learning environments" she lays out the pros and cons of the three online learning environments. She makes distinctions among formal learning through an LMS and informal learning through personal learning environments and social learning environments. What strikes me here is how little criticism social learning encounters - the con list is very short for social learning.

Most educators seem to be on board with social learning; yet, we in the corporate world, have a tough time selling the idea to our employers. How do you measure performance or mastery of skills and knowledge in a social learning environment? Without measurement of success and objective, quantifiable data - demonstrating the value and importance of social learning will continue to be a struggle. In the next few weeks, this is the area I hope to explore, and I will share what I find. Furthermore, I welcome any commentators who can point me to research in this area.