We extend the model of friendship networks developed by Brueck-ner (2006) in two ways. First, we extend the level of indirect bene…tsby incorporating bene…ts from up to three links and explore its impli-cation for the socially optimal and individual e¤ort levels. Next, wegeneralize the...

Based on the observation of best practice and detailed case studies we observe thatcompanies have started to organise themselves in loosely coupled networks, similar to themediaeval ‘commons’, and which we call ecosystems. These are far less structured than jointventures, but have at the...