Flexcoin, a site that described itself as the "world's first bitcoin bank," has closed after it got hacked and all of the bitcoins it had placed in online storage were stolen, the site recently announced. Flexcoin was attacked and robbed March 2 of all coins in its "hot wallet" -- a term that refers to bitcoin online storage -- the site said in an announcement posted to its home page. The attacker made off with 896 bitcoins, which at current prices across several exchanges would amount to roughly $600,000.