Since the 1990s, informal and personal networks have gained increasing attention as repositories of learning and innovation. Social network analyses so far largely concentrate on the impact of network structures on innovation processes. The role of social network dynamics and the interrelation of structure and agency in these processes however need to be more intensively analyzed. This research concentrates on learning dynamics in personal online business networks of communication and computing industry professionals based in the San Francisco Bay Area. The technological potential for online global multi-connectivity of the studied LinkedIn networks showed limited realization due to the users’ stickiness to their physical practice communities and localities. Physical social interaction served as the prime motor of network formation and maintenance.