Shadow banning

Shadow banning (also called stealth banning, ghost banning or comment ghosting^[1]) is the act of blocking a user or their content from an online community such that the user does not realize that they have been banned.
By making a problem user's contributions invisible or less prominent to other members of the service, the hope is that in the absence of reactions to their comments, the problematic user will become bored or frustrated and leave the site.^[1][2]

History

Michael Pryor of Fog Creek Software described stealth banning for online forums in 2006, saying how such a system was in place in the project management system FogBugz, "to solve the problem of how do you get the person to go away and leave you alone". As well as preventing problem users from engaging in flame wars, the system also discouraged spammers, who if they returned to the site would be under the false impression that their spam was still in place.^[2] The Verge describes it as "one of the oldest moderation tricks in the book", noting that early versions of vBulletin had a global ignore list known as "Tachy goes to Coventry",^[3] as in the British expression "to send someone to Coventry", meaning to ignore them and pretend they don't exist.
A 2012 update to Hacker News introduced a system of "hellbanning" for spamming and abusive behavior.^[4]
Craigslist has also been known to "ghost" a user's individual ads; and reportedly entire accounts.^[5][6] Reportedly, an ad is placed and confirmation is sent that it has been posted; the ad may be viewed in the user's account, but, if ghosted, will fail to show up in the live listings.
Early on, Reddit implemented a similar feature, initially designed to address spam accounts, though it is also used for general users.^[7] In 2015, Reddit added an account suspension feature,^[8] though still makes extensive use of shadow banning.
WeChat was found in 2016 to ban posts and messages that contain certain keywords without notice. ^[9][10]
In a study that looked at tweets from 2014 to early 2015, over a quarter million tweets were found during the one year period in Turkey to have been censored^[11] via shadow banning. Twitter was also found, in 2015, to shadowban tweets containing leaked documents in the US.^[12][13] In January 2018, a Twitter spokesperson told Fox News, "Twitter does not shadowban accounts."^[14] There is some controversy as to whether or not that statement by a Twitter's spokesperson is technically correct.^[15]
Also, in 2017 the phenomenon was noticed on Instagram, there certain posts have been seen to be unavailable to people who do not follow one in hashtag searches.^[16][17][18]