Professional Development is ill served by traditional ways of learning. It can profit from a Learning Networks approach, which emphasizes logistic, content and didactic flexibility. Learning Networks are online, social networks that have been designed and tooled to foster informal learning. Three European projects are discussed - idSpace, LTfLL, Handover - which have developed tools befitting networked learning. Each in its own way, the projects illustrate the benefits of a networked learning approach. This goes for all three flexibilities but in particular for the need to be didactically flexible. Finally, it is argued that formal education could profit from the tools discussed.