Reddit has banned the r/altright subreddit for “the proliferation of personal and confidential information.” That’s a rather clinical way of describing what’s often called doxing: posting details (docs) like the home phone number and address of someone a community wishes to harass.
Once this information is public, the person in question is open to all manner of personal threats, swatting, COD pizza delivery, and so on. The FBI recently released documents detailing its own investigations into death and bomb threats directed at women doxed and targeted by those gathering under the now rather ragged Gamergate banner.
It’s a problem in many communities and is frowned upon in pretty much anywhere with a modicum of moderation, with a few obvious exceptions like off-brand chan sites and private message boards.
It appears that r/altright was unable to curb the practice and was struck with the banhammer.
A variety of political subreddits were trending, suggesting that perhaps increased vigilance for and reporting of such tactics led to the ban.