Hello,
sometimes it seems possible to buy BTC at one exchange and sell it immediatetely at another one, making some arbitrage profit.
Of course, we have to take differences in the currency exchange rates into consideration, too.
Therefore I have launched a site showing those arbitrage opportunities:
http://nyse-group.de/bitcoin-arbitrageWhat do you think about it?
Comments/suggestions are appreciated!
Have fun,
Roman.
Thats actually a really good chart for seeing the balance between exchanges.