Users traded virtual currency, known as POP$, based on the likelihood of a certain event being realized by a given date.
A stock at price POP$95 would mean roughly that users believed there to be a 95% chance of the event happening.
The price of the stock was then used as an indicator of user confidence in that event and also as a way to increase one's net worth.
If you own shorted shares of the IPO when the prediction fails, you no longer must pay back your original price.
On the first of each month a prize was awarded to the user with the greatest percentage increase in their portfolio value over the previous 30 days (minimum value POP$250000).
Prizes were typically consumer electronics such as an 80 GB iPod or an LG Prada Phone.
Others dealt with current events, such as DIETDRUG, a stock on whether the new FDA approved Alli, a diet supplement, would be recalled in 2007.
Total Successes: 9 Total Failures: 10 Shortest Time on the Market: 5 Days (MOSPAM) PPX also ran a forum for its users to discuss current market trends, suggest new IPO's and discuss improvements for the exchange.
The magazine's June 2007 article claims that promising results from market based predictions were first seen with the 2006 congressional election.
Since the price action was based upon the games algorithm the predictive nature of a market is lost.
Of the four types of actions, Buy and Short affect the price of a stock, while Sell and Cover do not.
This led to a series of heated debates on the site forums around the viability and fairness of the PPX exchange.
Critics contend the effect of this stock pricing formula has damaged the predictive nature of the market and turned it into a who can push the button the most often type of affair.
PPX will impose heavy fines and/or trading restrictions on traders who make use of market manipulation for any purpose.
[citation needed] Four of the top players in the game admitted to using scripts to scrape the PPX site to provide them with up-to-the-minute changes in stock prices.
That fine, levied on the August 30, caused one player to lose the monthly contest and thus, an LG Prada phone.
The algorithm would move the share price by a fixed amount after x number of buys or sells.
The share price was mechanically set by the number of transactions and moved in fixed increments.
In a somewhat ironic turn, PopSci later implemented new rules outlawing trading and logging in with scripts, as well as adding a limit on prizes won by households.