The hacker collective Anonymous has alleged that accounts belonging to its members have been suspended from Twitter for "harassing" ISIS. Anonymous itself has been involved in #OpISIS, during which they have reported accounts involved in and sharing ISIS content to Twitter administrators. According to Anonymous, it has gotten 125,000 accounts suspended.
The Anonymous accounts involved in #OpISIS that were suspended from Twitter received no emails explaining the reason for their suspension, and some were reinstated after a brief period.
Source: Techworm.net, March 7, 2016.