Shill
A shill is a confidence trickster's accomplice who pretends to be an enthusiastic customer in order to encourage the victim, or mark. ("I can walk!", or "I can see!", or "I'll buy ten!"). The technique employs group dynamics as an element of crowd psychology: the victim comes to feel that he or she stands in good company, has good judgement, and should not miss this opportunity.The word is probably an abbreviation of shillaber, which has the same meaning, and appeared early in the 20th century from an unknown origin.
Examples of shills
In the case of betting that requires skill, the trickster and shill play out one or more times so that the shill wins and create the impression that it is easy to win. Sometimes shills are employed by legitimate gaming casinos, especially for games such as blackjack, and may have various purposes, for example, to provide "players" for an otherwise empty blackjack table in order to create a social environment, or more nefarious purposes such as deliberately playing badly in order to disrupt the flow of the cards, or to try to obtain information about winning players so they may be watched more closely. Unethical but seemingly legitimate casinos can even employ shills to illegally assist the dealer in cheating the other players.
In marketing, a shill functions as a provider of a testimonial - apparently unsolicited. In sales, the customer reference or the reference site equates to the shill.
In an auction, a shill bid is an anonymous bid placed by the seller in an attempt to raise the price. Shill bids can be used in real estate sales to encourage an offeror to raise the amount of their offer. Generally, shill bidding is illegal in the United States. Many states have laws that specifically make shill bidding illegal, and the consensus is that shill bidding, or any kind of bidding ring activity is also illegal under federal statutes governing wire fraud and mail fraud. With the advent of online auctions, shill bidding has become more common because it is more difficult to determine the real identity of an online bidder. Shill bidding can backfire on the bidder: if he becomes the highest bidder, he will be responsible for buying his own item (and may not be able to afford it, especially after the auction house takes its percentage).
The term is also used by illusionistss to describe a collaborator in a magic trick.
One could regard groupies as shills except shills are usually paid for their services.