weak ties walter values turkle Trust Telephone Technological determinism Tacit Knowledge Social Network social media ryan Reputation quantitative methods quantitative qualitative research Qualitative methods qualitative Online Reputation Systems online identity online games One laptop per child OLPC Notification Norms notification Nissenbaum networks music motivation L28 L27 L25 L24 L23 L21 L19 L16 L15 L13 L11 L10 L8 L5 L3 intrinsic motivation internet Identity homophily Heilbroner Frey Fischer facebook extrinsic motivation Ethnography Diffusion design crowdsourcing Crowding Out credibility badges ANT