Sockpuppet

A sockpuppet is an online identity used for purposes of deception within an online community. In its earliest usage, a sockpuppet was a false identity through which a member of an Internet community speaks with or about himself or herself, pretending to be a different person, like a ventriloquist manipulating a hand puppet.

In current usage, use of the term has extended beyond second identities of people who already post in a forum to include other uses of misleading online identities. For example, a New York Times article defines "sock-puppeting" as "the act of creating a fake online identity to praise, defend or create the illusion of support for one's self, allies or company."

The key difference between a sockpuppet and a regular pseudonym (sometimes termed an "alt" which is short for alternate, as in alternate identity) is the pretense that the puppet is a third party who is not affiliated with the puppeteer.