Thanks to a "lurker" for recommending this long explanation by the Jamestown Foundation on internal Chinese Communist Party policies and personalities in Xinjiang:http://slink.eu/vX

What is the mass line?
Official statements describe the mass line as a symbiosis between the party and the people in which local cadres ostensibly are better attuned to public needs and expectations.
Which concludes:
The appointment of Yu Zhengsheng as head of China’s Xinjiang Leading Small Group indicates a willingness to explore alternative solutions to the problem in Xinjiang. The fact that both of the party’s new initiatives in Xinjiang—the mass line and accelerated economic development— are drawn from existing Party orthodoxy raises doubts over how the far the center ultimately is willing to go. One Uyghur dissident recently dismissed Yu’s appointment in Xinjiang as “old wine in a new bottle” (Voice of America, May 31). The extent of the shift from a top-down focus on security to one rooted in the mass line will be become clearer as Yu’s tenure progresses.