Charlatan

A charlatan (synonyms include "mountebank", "crank", and "quack") is a person practicing quackery or some similar confidence trick in order to obtain money or advantage by false pretences.

Etymology
The word comes from French charlatan, a version of "Charley," a seller of medicines who might advertise his presence with music and an outdoor stage show. Ultimately, etymologists trace "charlatan" from either the Italian ciarlare, to prattle; or from Cerretano, a resident of Cerreto, a town that was apparently notorious for producing quacks.

A famous American charlatan was John R. Brinkley, the "goat-gland doctor" who implanted goat glands as a means of curing male impotence, helped pioneer both American and Mexican radio broadcasting, and twice ran unsuccessfully for governor of Kansas.

Subtle definitions
The person called a charlatan is being accused of resorting to quackery, pseudoscience, or some knowingly employed bogus means of impressing people. The aim is the same, however: to swindle his victims by selling them worthless nostrums, and similar goods or services, that will not deliver on the promises made for them. The word calls forth the image of an old-time medicine show operator, who has long left town by the time the people who bought his snake oil tonic realize that it does not perform as advertised.

Legal implications
Because of the connotations about intentional deceit, calling a living person a "charlatan" can actually be libelous or slanderous. Therefore, even with mounting evidence in support, it can be a dicey thing to just call someone out as a charlatan scam artist. So it's not advisable to call people like Peter Popoff, Jim McCormick, or Harold Camping, or Deepak Chopra, or Danie Krugel or Jerome Corsi or especially Donald Trump "charlatans". Indeed, Simon Singh got into a very expensive lawsuit after using the word "bogus" in an article about chiropractic medicine &mdash; even though he was later vindicated. These people totally aren't charlatans for what they peddle, by the way; they're just there for illustration and it's just a coincidence that people like Mehmet Oz, Gary Null, and the Geier family are being used as examples of people who definitely are not charlatans.

However, as noted by Penn and Teller in their first episode of Bullshit!, while [direct] accusations of running scams and calling people charlatans can dump you in the lingering boiling oil and melted lead of the legal system, calling such people "bullshit-merchant assholes" is perfectly fine.

Con artist
Closely related to charlatans are con artists. A con artist, or confidence trickster, is a person who attempts to obtain people's confidence in order to extract primarily money, but also goods, services, properties, and just about anything in exchange for… well, nothing at all really. Or at least, something with much less value than the poor fool is led to believe. The difference between con artists and charlatans is that the con artist relies on developing a personal relationship with the victim, while the charlatan usually does not. It is unclear at this time how they should be classified, as they do appear to be a ring species.

Oftentimes, the con artist will use some sort of woo or vague talks of some sort of conspiracy against them as to why you should trust him or her. The difference between a con artist and a woomeister is that the con artist knows they are full of bullshit.

Greed and generosity
Some cons frame the con artist as being 'down on their luck', and rely on either other people's greed: it always helps to let people think they are smarter than they really are. The glass ring con, for example, involves a person who 'needs' to go someplace fast, but all they have is a 'diamond' ring they are willing to sell for a fraction of its worth. The victim thinks he is practically scamming the poor sap of his diamond ring, only to find out that the victim paid a significant amount of money for a piece of glass.

Other cons often rely on abusing others' generosity, usually with some sob story of some type. A benign example being a homeless guy making up a story about why he needs just a dollar, but a few can get more elaborate and more insidious. These are especially damaging as, when the truth is revealed, people may question actual stories and cries for help.

History of con artists
Con artists have a "rich" history, probably dating back to before history itself. However, until fairly recently, most people lived in the same village for most of their whole life, with the only time someone moved being to acquire a spouse in a neighboring village; this meant most people knew most of everyone else, and scamming neighbors would be rather difficult as people caught on (and punished offenders).

With the advent of the railroad and other forms of transportation, it became easier for someone to travel through town, create some elaborate story, scam the locals, and move on to another town where they wouldn't be recognized. This led to a number of somewhat famous stories. Sometimes the con artist didn't need to move; they'd just scam the people passing through town who wouldn't recognize them. The expression "I've got a bridge to sell you" is a reference to an alleged con in New York City during this time, where con artists would "sell" the Brooklyn Bridge to naïve tourists.

(In)Famous con artists

 * 1) Victor Lustig, the man who sold the Eiffel Tower. Twice. At the time, the Tower was less "biggest and greatest erection in all of Europe" and more "high maintenance eyesore made from cheap iron". By pretending to be a corrupt French official, he secretly asked a number of scrap metal dealers to bid on scrapping the Eiffel Tower. Selecting a rather insecure but ambitious one as his mark, he "confessed" that he was looking for a bribe (thus the secrecy), and was paid the bid and a bribe on top. Not bad! He tried this a second time with a second set of scrap dealers, only for one of them to actually check with the authorities about the legality of this.
 * 2) Charles Ponzi, of Ponzi Scheme fame. He created an "investment" program where he would take money from new investors, cut himself a share, and then use the rest to pay off older investors without telling anyone what he was actually doing with their money. His investors would often reinvest their 'earnings' with him, which allowed the scheme to last even longer. When a reporter pointed out that he was making more money than actually possible, Ponzi sued (and won $500,000), which silenced further investigations of him. But as with all pyramid schemes, eventually it could not gather enough new suckers fast enough, and it collapsed. Afterwards, he moved to Florida where he had a lucrative business selling prime real estate swampland, which originated the phrase, "If you believe that, I have some swampland to sell you". Say what you want about the guy, you just have to admire his work ethic!
 * 3) James Addison Reavis, the man who (nearly) stole Arizona. In a recent treaty, the U.S. government had agreed to honor preexisting Spanish and Mexican land grants in American territory. Reavis manufactured a 18,600 square mile "Barony of Arizona" and a story as to how it entered his possession. He inserted falsified documents into many archives and even married a false heiress to support his claim. While the claim was ultimately exposed, Reavis had collected over five million dollars through the sale of land and investment plans.
 * 4) Bernie Madoff created a US$60 billion Ponzi scheme using fake stock market purchases. When the scheme collapsed, it caused great hardship to many people and institutions. He was sentenced to 150 years in federal prison.

The series of tubes
Now, with nearly the entire globe in contact with each other, people no longer need to leave their homes to find suckers or be scammed! Charlatans can create all sorts of webshites and mass email chains, ranging from the frothing lists of crazy to the insidiously well-designed to help alleviate you of back pains due to the weight of all your money!

One of the more infamous con tricks in the internet age is advance fee fraud (a.k.a., the Nigerian Prince); a person claiming to be a deposed noble (from a country that doesn't have aristocracy) (or a relative of a dead despot) has a vast fortune that is inaccessible due to legal troubles, and needs just a few bucks to hire an attorney but is willing to share his vast fortune with you if you can help out.