Anonymity [a] describes situations where the acting person's identity is unknown. Some writers have argued that namelessness, though technically correct, does not capture what is more centrally at stake in contexts of anonymity. The important idea here is that a person be non-identifiable, unreachable, or untrackable.

Scientists have found a tendency for many people to act rudely, aggressively, or illegally when their faces and names are hidden. More recent studies, however, have identified the positive features of anonymity, including digital interactions that might be overlooked in the midst of the attention that “trolls” and hackers receive.