a particularly simple type of hand puppet made from a sock

Sock Puppets are multiple screen names all controlled by one individual, they talk to each other even though they are one person. This gives the impression of discussion between different people, while one person controls the debate.

A sock puppet is a puppet made from a sock (or similar garment) which is placed over the hand of a puppeteer. When a sock puppeteer fits their hand into the closed end of the sock, the sock puppet can be made to "talk" with the opening and closing of the hand. The puppet's mouth is formed by the region between the heel and the toe, with the thumb forming a jaw.

A second member account that is used by the same person. This is sometimes used as a way to create the illusion of support in an argument.

an account created by one side taking part in a flame war

an account made on an internet message board by a person who already has an account for the purpose of posting anonymously

an additional OnlineIdentity used by someone who already has another OnlineIdentity for participating in a given community, particularly when done in a non-transparent manner and where the identities interact with each other in some way

A secret alias used by a member of an Internet community, but not acknowledged by that person.