When toxic online communities on mainstream platforms face moderation
measures, such as bans, they may migrate to other platforms with laxer policies
or set up their own dedicated websites. Previous work suggests that within
mainstream platforms, community-level moderation is effective in mitigating the
harm caused by the moderated communities. It is, however, unclear whether these
results also hold when considering the broader Web ecosystem. Do toxic
communities continue to grow in terms of their user base and activity on the
new platforms? Do their members become more toxic and ideologically
radicalized? In this paper, we report the results of a large-scale
observational study of how problematic online communities progress following
community-level moderation measures. We analyze data from r/The_Donald and
r/Incels, two communities that were banned from Reddit and subsequently
migrated to their own standalone websites. Our results suggest that, in both
cases, moderation measures significantly decreased posting activity on the new
platform, reducing the number of posts, active users, and newcomers. In spite
of that, users in one of the studied communities (r/The_Donald) showed
increases in signals associated with toxicity and radicalization, which
justifies concerns that the reduction in activity may come at the expense of a
more toxic and radical community. Overall, our results paint a nuanced portrait
of the consequences of community-level moderation and can inform their design
and deployment.

通过对两个被 Reddit 禁止的在线社区进行大规模观察性研究，本研究发现社区层面的管理措施显著减少了社区在新平台上的发布活动，但在其中一个社区中，用户表现出了毒性和激进化的信号，这也支持了减少活动可能导致更加毒性和激进社区的担忧。

平台迁移是否会损害内容审核？来自 r/The_Donald 和 r/Incels 的证据

Do Platform Migrations Compromise Content Moderation? Evidence from  r/The_Donald and r/Incels

Non-profits, as well as the media, have hypothesized the existence of a
radicalization pipeline on YouTube, claiming that users systematically progress
towards more extreme content on the platform. Yet, there is to date no
substantial quantitative evidence of this alleged pipeline. To close this gap,
we conduct a large-scale audit of user radicalization on YouTube. We analyze
330,925 videos posted on 349 channels, which we broadly classified into four
types: Media, the Alt-lite, the Intellectual Dark Web (I.D.W.), and the
Alt-right. According to the aforementioned radicalization hypothesis, channels
in the I.D.W. and the Alt-lite serve as gateways to fringe far-right ideology,
here represented by Alt-right channels. Processing 72M+ comments, we show that
the three channel types indeed increasingly share the same user base; that
users consistently migrate from milder to more extreme content; and that a
large percentage of users who consume Alt-right content now consumed Alt-lite
and I.D.W. content in the past. We also probe YouTube's recommendation
algorithm, looking at more than 2M video and channel recommendations between
May/July 2019. We find that Alt-lite content is easily reachable from I.D.W.
channels, while Alt-right videos are reachable only through channel
recommendations. Overall, we paint a comprehensive picture of user
radicalization on YouTube.

本文利用大规模数据分析研究了 YouTube 上用户的激进化现象，结果表明随着时间推移，用户越来越倾向于消费极端化的内容，尤其是从 I.D.W 和 Alt-lite 渐进到 Alt-right 频道，并且通过探究 YouTube 的推荐算法，发现 Alt-lite 容易从 I.D.W 频道中获得推荐，而 Alt-right 只能通过频道推荐获得。