Chasing Butterflies - Evaluating the organisational impact of informal learning

Informal Learning is a flavor of the month in L&D at the moment and if you believe the pundits and evangelists informal learning is more valuable that formal learning for increasing the skills and knowledge of staff. However does informal have a real and significant business impact, does it make a business and its staff better at what it does, and does it provide individuals and the organisation with identifiable increases in competency, efficiency and overall effectiveness and how can we evaluate this impact.