[bencxr]

People ARE buying/selling on Mtgox at 600. However, the price is not "real" because it is inflated by the inability to withdraw USD from Mtgox.

What is happening is that people are buying BTC on Mtgox and then transferring it to other exchanges to withdraw their USD.

For more accurate price information I suggest goign off coinbase or bitstamp.

[shocks]

This is not true. Look at the price on BTCChina and you'll see it's pretty much equivalent to the USD price on MtGox. Bitstamp and Coinbase are lagging behind because BTCChina and MtGox make up most of the volume.