The mobile messaging app WeChat has taken China by storm in the past couple years, swiftly becoming the largest standalone-messaging app, with more than 300 million active monthly users.
It has an ever-growing array of functions, from text and voice messaging to photo sharing. Perhaps most importantly, WeChat users also have the ability to form groups of up to 500 people.
That sets it apart in a country where the government controls citizens' ability to organize. It has enabled the creation of virtual, nationwide networks, and made WeChat the primary tool for Chinese citizens who want to organize around any given idea or cause.
Tencent, the Chinese Internet company that owns Wechat, also has an older, PC-based messaging app called QQ, which also has group chats, and a base of 800 million active monthly users.
Beijing University media scholar Hu Yong argues draws a comparison to Weibo, China's popular microblogging app that is similar to Twitter.
"What Weibo has done for freedom of speech, WeChat has done for freedom of association," Hu says.
China's constitution guarantees its citizens the freedom of association, but Hu points out that in practice, registering a non-governmental group is very difficult, and many non-registered groups exist in a legal limbo.
Black Apple Youth is one Chinese group that has made extensive use of Wechat to build a network. The non-profit is the brainchild of Victor Yuan, a prominent independent pollster.
On a recent weekend, Black Apple Youth held a leadership training session for college students.
The group's Executive Director Michelle Ling says Black Apple Youth has 20 Wechat groups, each of which has many subgroups.
"They're divided according to activities," she explains. "For example, we held a training camp in August, and all the participants formed a group. Then we also have 6 groups representing different regions of the country, as well as one for overseas members."
Members must be invited to join a WeChat group. You can't just search for a group and join. Experts see the way that the app builds on existing social networks as one of its "Chinese" characteristics. WeChat also includes a payment function, which groups use to raise funds or to vote by paying.
But Michelle Ling says that her group takes precautions when using WeChat.
"We don't encourage our young people to get involved in excessively radical discourse that may affect our organization's future, or takes political positions that are too obvious," she says.
Then there are people like Li Yiping, an activist based in Vancouver. He wrote an online manifesto whose title can be roughly translated as "Strategy for Regime Change."
His strategy is to use WeChat simply as an online tool to organize offline meetings of pro-democracy activists. He advises activists to keep all political discussions offline, and to avoid creating formal leadership structures that authorities can target.
Police have arrested many activists at offline gatherings. That includes members of the New Citizens Movement, led by activist Xu Zhiyong, whose methods resemble those advocated by Li Yiping. But Li says that overall, his prescriptions for mobilization have been effective.
"Through the use of this strategy, we've already broken through the Communist Party's ban on non-governmental political groups," Li says. "Behind the party's iron curtain, we have already found limitless space to develop. They can't monitor, much less suppress our form of organization."
This year, the government has also banned the unauthorized posting of political content on WeChat.
But it continues to allow people to form WeChat groups.
Media scholar Hu Yong says the government is a quick learner. If it chooses to, it can assert control over new technologies very easily. And just because the government hasn't clamped down on WeChat groups yet, it doesn't mean they won't do it later.
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