This paper investigates how users of Sina Weibo, a popular microblogging service in China, request information by posting questions to their online social networks. The fast development of social networks and social media such as microblogging sites has greatly impacted how people access and share information. Previous research has focused on how users share information on microblogging sites, but relatively less is known about how users use such networks to seek information. This paper addresses the gap. The data set contains 1969 question messages from 1939 users (information seekers) and 7997 responses to these questions from 3296 users (information providers), the profiles of the information seekers and providers, and their immediate social network (followings and followers). This paper examined the social capital and demographic characteristics of the information seekers, and the relationships between the information seekers and providers with regards to response rates and number of responses as indicators for information and social benefits of information seeking. Results show that 1) questions posted by female users and verified users and messages using the “@” sign have higher response rates; 2) about 70%-80% of information seeker-provider pairs are physically close and have reciprocal relationships. The study demonstrates the impact of the information seekers' social capital and their relationships with the information providers in regards to the outcomes of information seeking in Weibo social networks.