Sockpuppets

From Pagenation

A sockpuppet is an online identity used for purposes of deception within an Internet community. In its earliest usage, a sockpuppet was a false identity through which a member of an Internet community speaks while pretending not to, like a puppeteer manipulating a hand puppet.

In current usage, the perception of the term has been extended beyond second identities of people who already post in a forum to include other uses of misleading online identities. For example, a NY Times article claims that "sock-puppeting" is defined 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") is the pretense that the puppet is a third party who is not affiliated with the puppeteer.