What signs suggest a thread has become a "dogpile"?

A dogpile occurs when a large number of users pile onto a single person or comment with repeated similar criticism, ridicule, or downvotes, going beyond legitimate disagreement into something closer to a coordinated attack. It differs from brigading in that a dogpile typically arises organically within a thread rather than being coordinated externally — it is a crowd behavior rather than an organized campaign. The visible signs of a dogpile include a single comment or user at the center of a large number of replies, most of which restate the same criticism rather than adding new perspectives. A thread with fifty reply comments all essentially saying the same thing — "this is wrong" or "this person is terrible" — exhibits the structural hallmarks of a dogpile. The later replies in such a thread add very little beyond social signal, amplifying rather than contributing. The emotional register of the replies tends to escalate rather than de-escalate. In a healthy disagreement, rebuttals become more specific and reasoned over time as participants engage with each other's arguments. In a dogpile, the tone becomes more contemptuous, the insults more personal, and the responses less responsive to what the original commenter actually wrote. People are responding to the social pressure of the pile rather than to the content. From the perspective of the person being dogpiled, distinguishing between legitimate mass criticism and a dogpile requires honest self-assessment. Sometimes a comment is genuinely offensive or factually egregious, and many people independently responding with criticism is simply the community expressing its values. The dogpile dynamic becomes problematic when the proportion of responses vastly exceeds what is warranted by the original offense, when responses turn personal rather than issue-based, or when users who have not read the thread carefully join in based solely on the negative vote score they see.