Trading on the site began on March 17th, 2010
A major update to the site occurred in March, 2011. Among the changes were: smaller minimum trade size, 24 X 7 trading, and some steps to help ensure that payment will be made for trades that execute.
Though the site at one time was used for trading using PayPal as payment method, fraud caused the exchange to discontinue PayPal trading on June 4, 2011.
Important information can also be gained from the Bitcoin Market website homepage which shows a graph of the Bitcoin exchange rate (to US Dollars). This data is also offered in the JSON format.