That's the worst one of all as it contributes to people making stupider decisions and believing dumb stuff.
In the cell phone of a Chinese, such messages are ubiquitous. Taking the WeChat app by Tencent Inc. for example, I constantly read messages from my parents sharing such nonsense stories. They wouldn't stop even if you complained as their friends and alumnae shared these constantly. Subjects of the nonsense included but were not limited to: a) pseudosciences, e.g., Japanese scientists discovered that water molecules behaved differently when it was being scolded verbally; b) misinformation, like an explosion occurred or a child was taken by human traffickers, which could not be confirmed or the time of which is not specified at all; c) false/suspicious political/historical rumours which favours their targets (i.e. my parents); d) success stories and other click baits.
These stories were poorly made up but easily spread. Some were made in commercial purposes to attract more subscribers so that their network of rumours could expand. You cannot fight them all. You cannot sue them all. You cannot eradicate them all.
The one suspected notorious Company which helped GFW to grow is Baidu.
* Their flagship products, "360 Security", provides an alternative Windows-update facility; they take use of this to disguise another product of theirs, "360 Browser", as a Windows update: http://www.ipc.me/360-fa-bu-jia-xi-tong-bu-ding.html (Chinese source)
* "360 Security" and "360 Browser" spies extensively on the user, including uploading "suspicious" files for their "cloud antivirus" service, uploading the browsing history: http://www.ce.cn/cysc/tech/07hlw/guonei/201302/26/t20130226_... http://tech.163.com/10/1231/17/6P8I1JPR000915BF.html (Chinese source)
* "360 Security" was caught cheating in AV software tests: http://www.pcworld.com/article/2919554/tencent-qihoo-antimal.... More interestingly, after the denunciation from the test bodies, Qihoo 360 pretended that it quit the test voluntarily and announced that these tests are no longer suitable for "Internet-era AV software".
* They recently announced a "pregnancy mode" in their router product, due to widespread concern about the effect of WiFi signals on the fetus.
Their wrongdoings are uncountable.