We might expect that with social media people would share information beyond their already existing groups. However, when comparing sharing habits from 145 social media profiles of factory workers and 55 profiles of middle class Chinese in Shanghai, the evidence suggests that they don't.
Over a period of four months only one out of 6000 articles was found to have been shared in both groups. Though 5.1% of articles are shared within the factory workers group and 1.6% within the Shanghai group. So while most academic debates concern the problems of sharing information from the West into China, actually for all intents and purposes, there is no more information flow between two different social groups within China.