1) The document summarizes a study on why people ask questions to their social networks. It found that questions to social networks received more answers but questions to individuals received more in-depth answers.
2) Intrinsic motivations like perceived ownership of information and extrinsic motivations like reputation systems motivate people to answer questions. Expertise also contributes to participation.
3) The top motivations for asking social networks were trust in the answer quality, that the question was non-urgent, and to connect socially.