sock puppet
n. A fake persona used to discuss or comment on oneself or one's work, particularly in an online discussion group or the comments section of a blog.
Other Forms
Siegel is not the only professional pundit to be caught in a sock puppet scandal. This year, Los Angeles Times business columnist Michael Hiltzik was stripped of his column and blog for using fake handles on his blog and those of his critics. Economist John R. Lott, a scholar at the American Enterprise Institute, passed himself off as his former graduate student "Mary Rosh" to defend his work and attack critics.
—Cathy Young, “Journalistic ethics gone astray,” The Boston Globe, September 18, 2006
One of the joys of the Internet age is the great new lingo it is producing. To "flame wars" and "phishing" we can now add "sock puppet." A sock puppet, for those still boning up, is a false identity through which a member of an Internet community speaks while pretending not to, like a puppeteer manipulating a hand puppet. Recently, a senior editor at The New Republic got in trouble for some particularly colorful sock puppetry.

When Lee Siegel began blogging for The New Republic, he found, as many others have, that Internet posters tend to be fairly outspoken — and a good number of the posters on the blog were harshly critical. An exception was ''sprezzatura,'' who regularly offered extravagant praise. After Mr. Siegel was criticized for his writing about Jon Stewart, host of ''The Daily Show,'' sprezzatura wrote: ''Siegel is brave, brilliant and wittier than Stewart will ever be. Take that, you bunch of immature, abusive sheep.'' A reader charged that sprezzatura was in fact Mr. Siegel, but sprezzatura denied it.

The reader turned out to be right. …

Sock puppetry
may be rampant online, but journalists writing for their employer's Web site have a greater responsibility to be honest than run-of-the-mill posters.
—“Sock Puppet Bites Man,” The New York Times, September 13, 2006
1993 (earliest)
Everyone knows they're seeing two when there's only one. I happen to know for a fact that one is merely the sock puppet manifestation of the other's demented and sadly listing psyche. Like the Melanie ruse — Arthur getting in touch with one of his female multiples — it's all I can do not to just break into tears, when I think how the lad must be suffering inside.
—Dana Rollins, “Arty/Scotto,” bit.listserv.fnord-l, July 09, 1993