What is aggressive follow churn?
If you decide to follow someone and then change your mind later, you can just visit the person’s profile page and un-follow them. Aggressive follow churn is when an account repeatedly follows and then un-follows a large number of users. This may be done to get lots of people to notice them, to circumvent a Twitter limit, or to change their follower-to-following ratio. These behaviors negatively impact the Twitter experience for other users, are common spam tactics, and may lead to account suspension.