Someone told me this about two different exchanges,

 Yes, technically you could buy from New Liberty Standard before and during July 2010, but it wasn’t a true open market like we think of today. It was small scale, fixed rate trades directly with the operator, not an exchange with active order books. That’s why most people still point to BitcoinMarket.com as the start of real market pricing and broader liquidity.

What would be the difference between directly with the operator and not an exchange with active order books?